RBS Application - Grrrr

Fifer

My Sainsbury 0% deal runs out in September so I applied on-line for the RBS 9 month 0% Platinum card deal six weeks before Sainsbury's expiry date and asked fro a BT for the balance on the Sainsbury card (only £250 - I use the card as a rolling 0% facility for buying appliances and gadgets). I was accepted on-line and signed and returned the application form as soon as it arrived a couple of weeks ago. I did have to call the Call Centre as the application form detailed a freepost return address which was different to the non-freepost address on the included pre-paid business reply envelope. I was told to use the Freepost address (they'd had lots of calls about this) so did and sat back waiting.

Fast forward to today and still no card has been sent. I called the call centre to find out why to be told they are still waiting on the signed form which they now assume is lost in the post. Call me a cynic, but I suspect it's sitting on the wrong desk due to the !!!!-up with the return addresses.

Anyway, they are sending out replacement documents, but I leave for Majorca on Friday and cannot now rely on the BT happening before the last payment day for the Sainsbury card and I get back from holiday too late to make the payment, so I'll have to pay something before I go. RBS said that they could only cancel or change the BT by cancelling the whole application and starting again! I'm thinking of making a minimum payment (around £20) so that I'll only be left with a £20 credit on the Sainsbury card after the BT happens and I should only pay interest on £230 for the period up to when the BT happens (less than £4 I reckon). This saves me from being left with a £250 balance on the Sainsbury card if I opted to avoid paying interest by paying off the whole balance. Have I missed anything and is this what others would do? I know we're discussing trivial amounts, but the principle of avoiding interest is at stake.