Unfair treatment

My car's water pipe leaked in April due to a tear in the pipe. We were on our way from PE to Uitenhage the Sunday Evening and the car came to a standstill next to a rural area. My husband, who is a qualified diesel mechanic cut the pipe and rerouted it, because we felt it was to dangerous and Williams Hunt is not open on a Sunday. I knew and we made the decision to let the warranty expire rather then waiting on the dangerous road. 3000km later I had to take my vehicle in for the 45000km service. I explained the situation from April and instructed the mechanic to replace the pipe, I am willing to pay for it. When I got my car back, NOBODY communicated about the pipe, so I reckoned that it was fixed. 700km later the pipe burst and the whole engine broke.... When we opened the bonnet we saw it was still the old pipe. When I contacted Imperial Bloemfontein , they said it is because of the "tampering" in APRIL????? The dealer principal said that they did quote me on a new water pipe, but still haven't seen a or heard about a quote up to today. The then Quoted me R78000 for replacing the engine and the FIRST item on that quote is a water pipe. I feel that Imperial should pay for the engine, seeing that I was honest with them regarding the pipe and took responsibility for the warranty that has expired AND was willing to pay. The are bouncing around, trying to blame me, and stating about the warranty, but it has NOTHING to do with the warranty. They DID NOT do as I instructed and DID NOT qoute me on a new pipe. Also as a MAJOR INSULT to me as client: They then agreed to give me a courtesy car, but a few days later said I must return it, other wise they will report me and the vehicle as ******, because they didn't have a copy of my license. BUT the guy who booked out the car NEVER made a copy of the vehicle. I contacted OPEL SA, and they said they will investigate, because they can see on the job card that I did indeed requested the pipe to be replaced. AGAIN Imperial Bloemfontein went on about the warranty, but the can't even supply OPEL SA with the quote they claimed to have sent me regarding the pipe.