Unsatisfactory Service

I have a maintenance contract with Mastercare. On the 20th November I reported that my Defy oven was not working. on the 22nd a technician came and decided that the thermostat was faulty and replaced it 2 days later. when I used my oven again a few days later I experienced the same problem and phoned again on the 2nd December. I heard nothing from them for a whole week and phoned again on the 9th December. Two days later another technician came and told me that the timer was faulty. I asked him how long it would take to have my oven fixed and he told me that he has to wait for authorisation from Mastercare. I phoned again about a week later and was told that they still have to authorise the repairs. On the 21st December the technician phoned to say that he will be at my place to fix my oven. Today is the 24th December and I am still waiting. How do I prepare a Christmas lunch for a family without an oven? It is now 34 days and I am still waiting. Mastercare please remove your advert about your excellent service because it SUCKS. Unfortunately I have only kept 1 reference number which is CAR-134880-21, To all the staff at Masrecare who was involved with my query please get some training on customer service and I hope you also experience the same frustration as I have. I now had to book a Christmas Lunch for me and my family because of you