This happened to me once. mine is also condo unit. The tenant raked up electricity bill of $1k each month. I received a few notices from TNB regarding disconnection if still remain unpaid. But the tenant knows the way TNB works (probably they always doing this). They will always pay 1 month when they owe close to 3 months so TNB won't disconnect. However, I spoke to the TNB officer. She said that if I want to disconnect their electricity, I must pay up the arrears first, then only they can disconnect. I see no logic in that. Anyway, I managed to evict them and they did pay up all the money before leaving. Note my utility deposit only $500 but their electricity bill was close to $3k owing.