As for trusting the third party part, I ordered a pizza from the dominoes app and paid via Paytm.
The amount of 780inr was deducted from my Paytm and the Dominoes app said timeout and order was not processed.

Now I am out 780 +780(Paid by Card As I had to Eat right?) and I have no way to contact paytm support, all they have is an email, no customer support number or point of contact.

India going digital is not a bad thing, but the entity in control? should be chosen wisely.

PS: At least I had a card to pay and I had money to spare, what if someone was out of cash and that 780 was all they had at that time? Maybe they were travelling at night and taking a cab or paying for a medical bill...
there is a long list of questions but a very few legitimate answers.