You can go to nearest TNB office and request them to check the meter for tempering. Show them pictures of the suspected old meter.

If still using old meter, request them to change it as they will check the old meter before changing the new one.

Check meter they very efficient one so no need to wait long for it.

You are right but its always advisable to protect yourself and mitigate the circumstances as TS has not yet change name.

By doing this he has evidence for legal option to claim back from the previous owner and negotiate with TNB as he is not the perpetrator.