Barring the disconnections which should have been looked at as a potential fault (assuming it wasn't caused by internal wiring) then it looks like Home Telecom have done the same things as most other suppliers.
The supplier will be charged by OpenReach for a new person taking over a line, even if that line is currently active. Therefore most suppliers pass this cost on (and for some it is over £100).
The charge for disconnecting if you aren't migrating to someone else is also standard. Many other ISPs also charge this as, again, it is a charge levied by OpenReach on the ISP.
The Zyxel, as someone else has said, is a well known router. Not used them myself but don't believe there is anything inherently bad in them. And if it is a free router then that is more than some ISPs provide - some ISPs require you to provide your own router.
They may have handled things badly but in general their policies appear no different to a number of other mainstream ISPs.