PROLINE WYNBERG DESTROYED MY ENGINE!!!

I took my car to Proline, Wynberg for panelbeating works. Williams Hunt dealership had confirmed that it had no mechanical or electrical issues. I got my car back from Proline and it wasn't okay, I informed them that the car wasn't okay a few days later it broke down. Williams Hunt dealership assessed the car and found that Proline had fitted the wrong cap on the car which caused the head gasket to blow and cause engine failure. I informed Proline about this and Robbie, the director tried to blame me and suggested that a petrol attendant must have changed the water bottle cap. Since that didn't fly, they then said they disagree with the diagnosis from Williams Hunt and they want to check the fault for themselves. They kept saying they are busy checking th fault for 2 whole weeks and now that they realize that they clearly did a **** repair job they are now accusing me of causing the damage talking about a damaged radiator when I brought the car in for repairs. My car had no mechanical issues when I brought it in for repairs but post repairs it had a mechanical failure caused by a part that they had put in. The way they've messed up this job so much they keep shifting the blame between me and some innocent petrol attendant. They, particularly Kaylynne even avoids my calls and goes as far as hanging up the phone when I'm on the line. Disgusting customer treatment and lack of honesty. Absolute trash!!!