Accelerator not working on a Jetta Diesel

I just came back from the service dept of a local VW store. Well about two weeks ago my husband was driving along and then all of a sudden the accelerator would not work, he depressed the petal but no gas…nothing but the brake worked and lights were still on. He had to pull over turn off the car. Then after starting it up again it worked for a few minutes and then..it did it again. Well he called me up and I met him at the service station. Since it was in we had the timing belt replaced (78000 miles on the car,a 2003 Model). Three days later we picked up the car and they said our floor mats were to big and they went to far under the petal and hit the wires causing it to do what it did. OK, so we placed a new shorter mat in and a week later it happened to me again. I pulled over, threw the mat in the back and was able to get going again, for about 15min, it did it again. Took it straight to the repair department again (same one) and they took about a 45 min look at it and came out and said I probably need to replace the part under the petal (did not get specific info) but that all the parts look fine. Well I go back in to the car and on the way home (15 miles away) the accelerator failed 7 times!!. So here I am 15 min since getting home and I am just wondering if someone out there has had this issue and may be able to give me a better insight to what might be wrong. Sorry this is so long but I want to get my detailed facts out straight. As for previous problems we have had both front windows drop in to the door (recall), radio volume problems, car not being able to get out of park (that was fun…not) and engine warning light not being cleared from a repair pickup (not to forget to mention my tire was low and they did not bother to check it and I had to call them over before I left their driveway to fill up the tire….always check your tires on pick up!!!).