How about working the other way? Instead of having Spring forward to
your Google Voice number, why not dole out your Google Voice number as
your only number (or tell your callers you have changed phone numbers
and give them your Google Voice number) and have Google Voice forward
calls to your Sprint service? After all, Google Voice is a free PBX
with voicemail and forwarding to multiple phone numbers. The caller
calls your Google Voice number and it gets forwarded to your Sprint
phone number (and any other numbers you want, like work number, home
number, all cell phones, etc). If you don't pick up any of those phones
then they get voicemail at Google Voice (which you can have an e-mail
notification sent to you even with a transcript of the message). If you
get a text to your Google Voice account, it will forward to all your
configured phones (that support SMS) plus Google Voice will send you an
e-mail notification.
Stop trying to use Sprint as your voicemail, SMS, and PBX provider.
Switch to Google Voice for all of that. Use Sprint as one of the
numbers that Google Voice forwards to. Don't bother forwarding calls
from Sprint to Google Voice.
If you have Internet access at home (likely) then also look into having
free VOIP service with Google Voice (after the cost of the adapter). I
used to have a landline at home (in addition to my cell phones) but
dumped that cost and went to Google Voice as my main number that
EVERYONE calls (and then Google Voice forwards to my other numbers). To
add VOIP at home, I got an Obitalk adapter: connect any phone to the
adapter, connect the adapter to the cable modem. I get and make free
calls using Google Voice to the USA and Canada. I had MagicJack in the
past but they has quality problems, plus you had to pay annually (or for
5 years) to use them. Google Voice is still free.
If you want to keep your Sprint number as your main number, you could
transfer that number to Google Voice. That's what I did but with a
twist. Google Voice only lets you transfer cell phone numbers to them.
So I transfered my home phone to my cell phone (for free) and
transferred my "new" cell phone number to my Google Voice service (I
think that was a $20 one-time charge). The Obitalk adapter is $50 but
that's a lot cheaper than having to subscribe to magicJack or other VOIP
providers. Yeah, there's Skype but that VOIP is free only when calling
other Skype users. Skype sucks. I have 60-minutes free per month with
an Office 365 subscription but I've had no need nor desire to use Skype
for phone calls (only only a tiny interest in Skype-to-Skype "calls").
See
https://www.obitalk.com/info/googlevoice for info on the adapter.
Obitalk's quality for VOIP calls is a lot better than what I had with
magicJack.
No matter which cellular provider I have at the time or a multiple of
them, everyone calls my Google Voice number which rings my home VOIP
phone (via the Obitalk adapter), my work number, and all my cell phones.
I don't know if there is a limit to how many phones you can transfer
calls coming into Google Voice.
On my Android phones, I added the Hangouts Dialer app. That does 2
things. One is to let me use the Internet for free VOIP calls. The
other is to present a prompt as to which dialer to use for outbound
calls. I configured Hangouts Dialer to always use Google Voice. That
way, when I call others, especially after returning a call to my Google
Voice number that I picked up on my cell phone's number, the caller sees
my Google Voice number just as if I called from there. Basically
Hangouts Dialer calls a regional Google Voice hub to spoof that my call
originated from Google Voice. I don't have to tell someone not to call
back on what shows on their caller ID and instead my Google Voice number
because what they see in my caller ID is my Google Voice number.
Stop trying to get Google Voice slaved to Sprint. Instead slave Sprint
(and your other phone numbers) to Google Voice. Then you'll have all
the features of Google Voice regardless of what Sprint decides to
support or not. If you change to a different cellular provider, your
Google Voice number doesn't change. No having to tell everyone your new
cell phone number.
Google Voice - when used for incoming calls that it forwards elsewhere
(it is NOT the slave) - also has spam filtering. It's similar to using
NoMoRobo with your [home] landline (which is free but their Android app
costs money for a subscription). If you still get an occasional spam
call, you can mark it as spam to thereafter block it and vote that
number as a spam source (but be aware that spammers can and do spoof
their phone numbers). You can screen incoming calls: the caller has to
say their name, then your other phones are called and you hear their
name. If you hear blank, yep, another spammer. If they don't give a
name (any name, really) and they don't leave a message in voicemail,
well, it was an unimportant call. Along with Google Voice's screen
feature, its anti-spam/robo filtering, and with my phone configured for
silent ringtone with each of my contacts configured for a ringtone, the
only time my phones ring is when a contact calls me. Other calls have
to leave a name to get me to pickup or leave voicemail. That eliminates
a hell of a lot of spam calls.
Since you're using Google Voice, then use it as your primary phone
service and slave the other phones to Google Voice. It's a waste of
features to make Google Voice the slave to some other phone provider.