I have been using LOOP Mobile’s service for a very long time in mumbai, and trust me, i’ll definitely recommend this to anyone.
Before switching to BPL(formerly name) I had mtnl’s trump which was way too bad. But after I switched to loop, I barely had any call drop problem.
Moreover their pricing is also good, and I am completely satisfied with their service. Its 100% recommended by me, you can go and use it without any trouble.