Bad service and warranty

I am very disappointed in D3L automotive and the way Trevor handled my complaint in a very arrogant way. I took my opel to D3L in june for a cilynder head overhaul as my timing belt came off. Fetched my vehicle and the next day the lifters was noisy. I immediately phoned and reported the problem. I was told to give it some time as it should disappear, and if not I should bring in the vehicle. Two months down the line(****m) I still have noisy lifters, specially in the morning. After driving ****m I took my vehicle back on the 15th of august for my engine checkup and to have a look at the lifter problem. I was then told that its a hydraulic part that failed and its no ones fault. D3l want to charge me another R3500 to replace the noisy lifters after R12500 has been spent on my engine. The head was done by D3L and I should not have this problem being dumped on me. Exactly why I did not take my vehicle for a quick fix at a "backyard" mechanic. I chose D3L for good and quality service? What is my six month warranty for? I now proudly drive a vehicle sounding like a tractor with a very proud service and maintained by D3L automotive vinyl sticker on my back window as adverti*****t. Altleast its a good quality vinyl sticker.