Reactive insurance solutions no engineer visit radiator issue

Howdy !

After experiencing a couple of costly boiler repairs , I eventually found a company that would service my central heating system for a monthly premium. This company is called reactive . I found them through Giles heating who fixed the boiler .
Fair enough . The policy started on 29th June 2018 , £ 17.56 pm
I nearly got declined at credit search, but they have more than one way to check credit rating and I passed. Not too sure if this is relevant

So, in mid December (14th?)can't remember exact date , I noticed two radiators are cold at the bottom
I called reactive , and was told an engineer would be in touch .
I do expect that they would be busy around this time ,and I didn't press the keypad for urgent priority .
I had to call them again on the 18th , an engineer did call me back .
He sounded busy . He said that he would get back to me . He said it sounded like a power flush . He never called me back .

In the meantime , I looked at my policy. A powerflush is not included
Balancing is not included . The policy is for 'home heating plus' .
What is covered is : the central heating including boiler , pipe work,radiators ,thermostatic valves and thermostat .

So, on 4th of jan I sent an email to the complaints team.
I was obviously polite and told them that I understood it to be a busy time before xmas. However, I did ask them what am I actually paying them for ? I did say a lack of customer care ,and potentially paying a lot more if the problem rads are to be fixed.

I received a reply on the same day, with the complaints procedure arttached. The chap did say that the complaint will be investigated fully and I will receive a response ASAP .
I was told that he contacted an engineer today and the engineer will contact me "to arrange an appointment for next week "
The week has passed. I sent an email on Friday 11th and received an automatic reply telling me to ring no/ email engineers .

Which brings me to today. I phoned from my mobile and got cut off.

So, I was thinking of just stopping direct debits . If I do that , it means I've paid £105.36 for nothing . I was going to wait till boiler has been serviced, then change them for somebody else.

Not sure what to do here. They have great reviews on trustpilot, sound professional on the phone . One thing I did say on the email , was that them using contractors doesn't fill me with confidence.
That was a bit naive on my part, but when I was told " we"ll try another contractor " when I told them I wasn't contacted since the 18th Dec ,it may have unintentionally rubbed them up the wrong way.

Not sure what to do here.

Please can someone advise

Thanks in advance