Horrible service from Rain network services

I took out a 5G internet package in Dec 2021, from the word go the internet was giving me problems hardly connecting and after numerous attempts of help from the service provider and not winning , I decided to cancel the service as it wasn’t doing what it was intended to do. There my problems started I was told someone would contact me to come and collect the router and that never happened, after several calls and emails I still haven’t been helped. In January I switched off the router completely around the 6th or 7th I still got billed. The Device is still not collected and I’m continued to be billed for a service that I am not using it has never been switched on the whole of February , my crime is that the device is still with me when there are the ones not collecting it. I missed a call from them on the 8th of February and I was sent an email and sms which I did not respond to now that is what they are using against me. All I need is for the service that is not working to be cancelled. Mind you I’ve got another sim with them a 4g which is working very well and I ended up upgrading it instead but that is not enough for Rain. I want to cancel that as well now after all this horrific experience but I don’t know how. I’ve got numerous reference numbers below is my first reference number when I cancelled the service