This very likely tampered meter case, TNB won't simply accused one as otherwise go Court they will lose  😅

What was your average bill b4 March meter replacement ?

Currently when usage is back to normal after mco and everyone is at home, still 20 ?

What was the billing b4 mco ?

On the assumption that you are right, then you should stand your ground and insist that TNB proved that you were the one to have tampered with the meter 😇

Do noted that untampered meter are security tagged with serial rivets which cannot be duplicated unless you are willing to spend a lot of $$$
to do it 😅