Take SP didn't work?

Anybody else had this problem recently. Three times over the last couple of days I have requested odds and checked the "take SP" option. Later on I discovered my bet was Unmatched. First One I presumed I had forgot to check the box, But 2nd and 3rd time I doubled checked I had. Betfair simple refuse to accept anything other than it was my error. Fortunately these were only small bets and were not life changing, but something odd definitely occured? Anybody else suffered a similar fait?