Sorry for the delay in getting back to you, this sounds like a control panel failure.
Unfortunately it requires an engineer visit to strip down the unit, clean the circuit board and test the contacts, most likely the switch has failed, however it could be the control board which is getting confused.
If you provide your post code, and model number, I can recommend an firm to come out and resolve this fault for you.
No problem I would highly recommend you use RBS, their number is *****(###) ###-####or 07860 693063, they are a local firm.
I have referred many customers to them over the years, and have always had excellent reviews and feedback with the quality of their work.
I will chase them up tomorrow, did you leave your details on his mobile?
I am very sorry you have not had a response from RBS, I will follow up with them tomorrow.
However after speaking to my colleague he suggested Domestic Services, they are located in Sheffield and he advised have a good track record with repairs, they can be contacted on 0114(###) ###-####
Let me know how you get on. I would be reluctant using anyone else.
If they wont take the work, I find out why RBS havent got back to you.