Bad welding exhaust, leaking

Asked to decat my car, they charged me for it.

I paid and got my car back, drove around and heard a tin noise, I took it elsewhere to check my exhaust.

They damaged my whole exhaust with very bad welding and bad workmanship. It was leaking.

I went there and told them I want my money back and they need to get someone else to do better work.

It costed me double to end up fixing their mess as I don’t want them touching my car.

They told me they don’t want to give me back my money and they happy with that work.

This is not fair if they doing this to people’s cars.