Appalling ADT / Fidelity service

I have been a customer of ADT, now Fidelity ADT for about 20 years and have to say I am unbelievably frustrated and disappointed and annoyed with their appalling service levels recently. In Sept 2020, I needed the technicians to come and fix some broken zones. I called and was told I had to have the sales team round first so they could quote what was needed. Sept 15th - First sales guy didn't pitch the first time (kid had a marble up his nose apparently), the next day he got the time wrong. He never reverted with a quote. I called and chased up and they sent another sales guy round as the first guy had been fired. I had decided it was also perhaps time to have a quote for beams too. 2nd guy comes round and doesn't send a quote, so I have to chase asking if they want my business. Eventually it comes, by which time I have asked SecureRite and Vetus Schola to also quote. They come round and within 24 hours they have each sent their quote. I decide to leave ADT and go with SecureRite, who can do the installation the following week. I call ADT to cancel contract and they say they'd have to come and extract the alarm system as it is rented. I ask for a copy of the contract confirming it is rented as my monthly bill is for monitoring services only. The last thing I need is for them to come and rip out the alarm and leave holes and damage. I call their customer service and their sales manager comes back to me and 'begs me to stay' as a customer and he will half my monthly fee and will get the sales guy to make contact and send through the paperwork. Although it feels like *********, which I tell them, I reluctantly agree to stay with them. The sales guy doesn't call. I phone the sales manager back again and he says he has just spoken to the sales guy who says he has spoken to me and it is sorted....I tell him that's a lie, the sales guy hasn't called me, He does about 10 minutes later and says he will send the paperwork to me and get it sorted on Monday 12th Oct. On Mon 12th I get the paperwork through and confirmation of deposit required. I sign the paperwork and pay the 50% deposit and email the sales guy with proof of all this and request an installation date. Then I hear nothing.....no confirmation of receipt of signed paperwork or acknowledgment of deposit. On Weds 14th Oct, I call the sales manager again to tell him I have heard nothing and no installation date. He obviously calls the sales guy who then sends me a mail saying the technicians are crazy busy but my installation is booked for the following Fri 23rd....However we are on holiday then! He didn't call to find out when we would be about and when was a suitable date and as of now he hasn't responded to my email requesting an installation date when we are actually here. I am appalled and feel totally *********ed by them, I have to stay or they come and rip out my alarm....which I have had for 20 years.....