Missing or Loose Fuel Cap

OK.. I recently purchasd a used 2007 LR3 for my wife.. got it less than two months ago. Sincw then, it has eben in the shop 20 days now, after dropping it back off today. The recurring ssue that they can not sem to get fixed is Missing or Loose Fuel Cap. This is the fifth time I have taken it to them for this. SUre, it seems petty, but after it does it for a while, the chekck Engine light comes on. They ahve replaced the pump and sensor that sends this code from the tank 3 times now.. I keep asking have they thought to maybe put a new gas cap on it?? They tell me that it tests fine.. Getting very frustrated. Oh, and also, they have had to replace the coolant sensor, air suspension compressor, and the rear wiper motor. Mind you this is all in 2 months time. I am expecting a call from my service advisor and the service manager at 9:15 this morning, but I alsoI told them this morning that if the issue is not fixed this time, all further communication will be with my attorney. In Texas, Lemon Law applies to used vehicles also as long as they are within factory warranty. Vehicle only has 28,000 on it.. Very dissapointed in my first, and surely last, Land Rover purchase.