Transmission lines keep "blowing"

We had a Remco lube pump installed on our 2003 Chevy Impala in summer 2009 & had towed for over 3 yrs w/no problems. Last spring we had a car fire due to a hole in a trans line to the lube pump. We had the car towed to the local (small town) Chevy dealership for repairs. They installed a new line. Within 2 days we were driving when the car slowed & refused to move. There was trans fluid all over the road. Had it towed to same garage. They said that the line they replaced had "come loose" & that it was now fixed even better. We returned last fall to have the rest of the old trans lines replaced with new ones after we had yet another leak. This spring another line developed a long crack, was leaking & had to be replaced. Within 2 days the car again dumped all the trans fluid on the street & came to a halt. We again had it towed to the same Chevy dealer. The hubby insisted that he talk w/mechanic who did work. He stated that the first repairs were done with what they had in stock- which was gas line & vacuum line. This time, he insisted that he obtained the proper high pressure line from a parts store, & used double clamps. He assured us that we would have no more trouble. That was Wed. On Friday all the transmission fluid was on our garage floor. We tried to hook the car to the motorhome to tow it to the dealership in a larger town...the lube pump sprayed fluid everywhere. We called a tow truck for the fourth time (and the sixth repair). My question is: is there any way that the lube pump could malfunction or be hooked up wrong that would cause a high pressure situation that would blow out these lines...and/or is this dealership that incompetent? Any ideas out there? This has been a great car & a great toad...we would hate to blow it up at this stage!