We're sorry if you feel the questions are "unnecessary". We have to ensure that we gather information for a reported issue and if we are asking such questions, it means that not all the information has been provided on the initial form. Unfortunately, some information entered is either incorrect or the fault type selected could be mismatched to what is being stated; these are things we have to check.
Much of what you've claimed however is incorrect in regard to Openreach works and line checks we can and do run on faults.
Openreach do routine cabinet reboots/software upgrades and these are not always notified to us on an exchange or cabinet level. This is not unique to us in any way. Genuine outages however are recorded and published when service affecting.
We can, of course, run a line check and this is one of the standard things we do when a report is received. However, as you do have a line, if the Openreach line check is clear (returns no detected fault) and based on the issue you are reporting, checking for a clear dial tone amongst other things are standard diagnostic checks.
If you've requested to cease your service which it sounds like you have, a cease fee, charged by Openreach, is passed on at cost. Unfortunately, if you've not followed the steps within your portal, this delays your cease request but could have been avoided by doing this on the first instance