I received my BT line rental paperless bill a few days ago and noticed that they have changed the amount charged for from 3 months to about 3.5 months (They are trying to get the bill date to reflect the term of the bill or something). But have only credited 3 months paper-less billing.
I admit this is only about 70p loss - but I thought - 70p of of every BT customer will add up! - I hate monopolies so E-mailed them to complain.
Now the deal bit - They creditted my account £5.00 due to the mistake (Sorry - deliberate attempt to rip people off). [The first E-mail back from them said the bill was correct - so I replied to say it wasn't]
Thought I'd share - you may want to check your BT bill if you are on paperless billing.