They are probably under the assumption that your wife and daughter are in Canada, hence asking for communication proof.
Still, you can provide them with current relationship evidence:
1) Photos of you, wife, and daughter at celebrations (such as child birth. baby shower etc) together with both side family and relatives (show pictures with different people at the same events)
2) Proof of anything held together in your and wife's name - rental lease, property ownership, bank accounts etc
3) Pictures at home (everyday life)
4) Communication via email, phone log and chat messages for the time that she and child WERE in Canada while you were in India
5) Current phone logs - spouse is still on speed dial even when you live together!
6) Gifts bought for wife and daughter (and from wife to you)
That's all I can think of. Essentially, fill all time periods from the day you applied for sponsorship.
I would also highly recommend showing some commitments your wife has back in Canada (rental agreement/house/car owned, job with leave of absence/offer letter, deferred studies, parents there..) They might doubt intention to go back to Canada if your wife has been with you since sponsorship application, so anything to prove her strong ties to Canada.
If your meds are expiring, you should send all this ASAP to avoid further delays.
