Just some questions to British people suffering these 'ups and downs' with BT ...
- Is British Telecom the 'only' ISP in the UK? I don't think so.
- So you'll have (for sure) a number of friends/relatives using the services of another ISP, right?
- Are they also suffering that hidden blackmailing? If the answer is no, then BT is guilty.
The bottom line ... change your ISP as soon as you can ...