I have a Very mail order catalogue for many many years, have a huge credit limit and only every owe it £100 - £150 at a time at most. Maybe a couple of day late payments but NEVER been in default, never not paid etc etc. can they just send me a letter increasing the general interest rate from 14% to 26% a nd make it apply to the amount I have outstanding. I thought it would be on future orders but it appears it's on everything I owe. Can they just randomly put the rate up? I didn't order goods at 26% can they legally just effectively charge me what they like.