Lamona Gas Oven

Took out a Repair and Protect plan as my gas Lamona oven control button had broken and also the cooker was not switching itself off despite being isolated from the walls main switch causing the flame to remain ignited. A repair was carried out to the Lamona cooker whereby a new ignition was fitted and also new replacement knobs. I was at the time under the impression this was now ‘safe’ to use. Prior to the engineer leaving he mentioned that the rubber trim around the cooker door was faulty and he would get a replacement posted out to be fitted by myself.
An engineer was again called out as I had returned home to a house full of black smoke; my daughter had used the oven and turned it off after cooking unfortunately it had not turned off despite being repaired only 4 weeks earlier and had remained lit for over four hours, thus causing the units around the cooker surround to melt. The engineer rang me to discuss the problems prior to visiting and said that due to the seal around the cooker being obsolete it wasn’t worth him coming out to visit as he couldn’t repair it. He was going to report back and someone would contact me in a few days.
After a couple of weeks and a lot of phone calls I was informed that my plan was now cancelled as the cooker couldn’t be repaired despite the original problem still causing issues. Due to a seal the appliance is classed as un-repairable, surely after the first visit this should have been picked up and I should have been informed. The policy then cancelled not wait until further damage has been caused then cancel the policy, this I feel is very unprofessional and certainly not a way to conduct a business by choosing when a policy is conveniently effective depending upon whether an appliance can be repaired especially after the original problem was obviously not correctly mended.
Refunding my direct debit payments is certainly not acceptable especially now as I have an unusable cooker and units to replace of which I am hoping to be able to get more of. I trusted that I would receive a professional service but to date I am left substantially out of pocket due to a cooker that is dangerous to use and part of a kitchen that needs to be replaced.