Comcast mail bouncing

[di...@dmargulis.com]

My Web hosting company (DiscountASP.net) runs strict policies on their
mail servers and they are now bouncing quite a lot of incoming mail
from Comcast customers. DiscountASP points their fingers at Comcast,
saying they have several servers that are not configured properly
(missing PTR records). Comcast says that, no, they're clean as a
whistle and it must be DiscountASP's problem. Meanwhile I'm stuck in
the middle--along with the various clients' sites I also manage on the
same server and any other customers in a similar situation. I keep
telling these guys that the two companies have to figure out the
solution--it's not my responsibility. But I'm the one suffering the
consequences. Generally, I've been quite happy with the service
DiscountASP provides, and I don't want to go through the hassle of
moving seven sites to a hosting provider that may turn out to be worse
rather than better.

Anyone have any tips for getting these people to talk to each other?
Any magic incantations or names of federal agencies I should mention?

Thanks,

Dick (posting from a hotel room and therefore through Google Groups
because I can't post through Supernews from here)