If you want to create the account "eduard.coscodan" you'll have to
wait the approx 9 months Google is waiting to release the name again.
Alternately you could try to get "eduardcoscodan" re-activated, but
change your reply-to address to "eduard.coscodan" and have everyone
list that.
This happens with any email account. The server will never accept a old name for reuse and also the other name you have tried is the same as your yahoo mail address, that is why it is not accepting it. Try again with a different name maybe coscodo...@gmail.com or so..... you use the options available to create new account by suggesting a different name