Bought a clay sim card in delhi and it turned out to be a bad choice --- opted to use a clay sim card in London only to avoid massive bills, but it turned into an overall bad expereicence. Network was unusually low most of the times, despite calling their customer centre so many times, they didn’t help. Anyhows because I had paid for their services, I continued using ensuring I was using it minimalistic. I came back to india to a bill of close to 21,000/- rs. That was even more than what I usually spend on my indian number there. With no network and mostly receiving calls, I was billed to the tune of 21,000/- rs.  Clearly cheating the customer on bills. Its taken me more than a week to follow up on my itemised bill with no response yet. Never using a clay sim card again.