Bets voided by Betfair

[mellenec]

This afternoon, I placed in-running , with t BA, a dozen Lay bets followed by a Back lay(on the same horse) within a few seconds time.
I could see a profit in the column profit , however I later realized that Betfair had voided these bets.
It is not the first time I place several bets of this kind in a row, and I don(t remember they have been voided.
For which reason? Is there a way to avoid this?

[GaryRussell]

Betfair must have had their reasons for voiding the bets. It won't be anything to do with Betting Assistant, they would have been voided no matter how they were placed. You should query this with Betfair. There is no way to prevent bets being voided if Betfair decide that is what they are going to do.