Appalling inexistent service - I want OUT from ID mobile but I can't. Cheaper is not always better is it ...

This is appalling. iPhone 11 Pro user. I moved away from O2 in order to save a few pounds (silly of me) and I have now been with ID mobile for just over a  month - and I am really struggling with it. I initially opted for an eSim but most of the time I couldn’t make phone calls, especially, I seem to have noticed, to other non iPhone users. So three days ago I have opted/replaced the eSim for a physical sim card and inserted it into my phone. At first things seemed to be better but three days later, I still seem unable to make calls to certain numbers. I have an existing claim that’s been escalated through the (pretty useless sorry) live chat agents three or four times now but i am still waiting for the so called ID ‘technical department’, mentioned by the live chat agents continuously as the ones who need to look into the issue but in reality “ghosts” which have never ever once contacted me back despite my issue been now raised several times, to get back to me. I also don’ t understand why I need to have two options in my phone settings in order to make calls: “Personal” and/or “Primary”. What is that? Anyne has any similar experience/tips? However, I think I now really want out from ID and my next step if my claim does not get answered/resolved very quickly will be to ask them for a letter of deadlock and then I will have to wait quite a few days before I can open a complaint through the Ombudsman if ID don’t supply me with one. So, I am saving a few pounds compared with O2 but I am unable to make calls (and I do get charged 55p for each MMS now)!