Thailand is... different. But since it is a European owner, let him know that you will fix the heater, and take it off next month' rent. He may agree. Otherwise, you may just have to get it fixed on your dime. It probably won't cost you too much anyway.
And remember. This is Thailand. Getting mad at the locals will get you nowhere.
, I am wondering if he was reporting the same address. Or not reporting an address at all. I am currently travelling SE Asia using Thailand (different parts, but mostly Bangkok) as a base, therefore travelling visa exempt. I make sure to not just stay in Bangkok, but travel Thailand.