AEG D41015B Double Oven

Installed my AEG D41015B Double Oven all fine, however, after using a couple of times suspected fault with main oven it just kept getting hotter no thermostat control the third time of use the cooling fan operated for 55 minutes to cool the oven down.. Have been unable to use it since. Contacted Service Force AEG agents as instructed in manual. Engineer visited and confirmed Theremostat NOT working. As it was within 28 days of purchase decided on replacement, oven ,however, discovered oven had been discontinued and Appliance Direct and AEG had no stocks available. We ordered the product because we wanted a BLACK oven and as our previous AEG oven was 14 years old and had no major problems decided on AEG despite several friends advising us that the quality was now poor. Not being able to get a like for like replacement decided to go with replacement thermostat through Service Force. Appointment made for Engineer to fit part required on 28 October this morning (27th) received a call to cancel this visit as the part was not available. I was told that it should be in stock sometime next week and will be contacted again to arrange a repair appointment. Contacted AEG UK at Luton to see if they could confirm that the thermostat (which I consider to be a BASIC part and would expect Service Agents to carry stocks of) is available. AEG were unable to give any help other than it was OUT OF THEIR CONTROL Service Force would deal with it. That is not what I call customer service. I would check other manufacuturers.