1)I think you should keep it! When they make a mistake all the time ripping off and stealing from millions of customers including tons of jews, making billions that is for sure that they don’t give it back.
2)They even give you a hard time when you point it out and ask for a refund. Many time refusing.
3)Also many times it’s no mistake, they blatantly steal from all their customers with hidden fees and charges (nickles and dimes and dollars that add up to serious millions)
So I think it’s a drop in the bucket, and the least you can do to offset these Companies HaGazlonim, is to keep it.
I’m not talking about personal stores or banks that you enter, which you must immediately return making a K”H, but specifically cell phone companies that are ALL known crooks.
Also you have to consider that they will realize on their own and retract their credit.
If you tell em you’re jewish, and return it it might make a K”H
though, even for a second, that is, if the Pakistani operator even knows what Jewish means.