desibois I guess most options are already covered above.
If the intention is to only add money to the wallet without charges (and not to earn rewards for utilization of credit card limit), then Credit Card to PayZapp, and PayZapp (Virtual) Card to Paytm via Uber is still a valid option.
I was able to add 40k+ to Paytm over 2 days (20k+ on day 1, and 20k+ on day 2). I was also able to move it to my Bank Account without any charges (as already confirmed by several above that Paytm wallet to Bank is free).