FREE VOUCHER IS COSTING ME MORE

I recieved a R200 voucher on first purchase (min R400). I added 3 items to my cart coming to R417 and entered the voucher, bringing it to R217. Entered my card details and then R417 was taken! Emailed them immediately (19/11 to which they still haven't rep****!) Phoned CC today and the guy said I'll have to cancel the order and then they'll refund. But now the voucher has expired!! Thanks for nothing...