I have mainly used paytm when I have used grofers.com. the main issue is if some item is not delivered cashbacks will get completely gone!
moreover paytm cash offers from bourbon biscuits too where not given and offer is over error is received.
Paytm is very slow to process refunds for any failed transactions. even if payment fails and you are unable to buy the item. the money will stay in paytm wallet only.
For large transactions wallet upgrade is also required which hinders the usage. Once email id is set to mobile no it can’t be changed. so if mobile is lost so is your pauy paytm cash. Be careful while using this wallets as is your phone is lost you may need follow very long route to get your money back. Moreover 4% commission is present for every transfer to bank. Avoid if possible.