I paid £31.50 a month direct debit. After three months the account is £5.09 in debt. So BT has put my monthly Direct debit up to £42 a month (£10.50 increase). On that basis I'll be over £20 in credit at my next bill. I'm not flush with cash so begrudge over paying. If put the DD up by £4 a month to £35.50 I would pay the £5 debt off and be nearly £7 in credit. Is BT exploiting the situation?