Why do you keep cancelling bets?

When I put an order into the market you often (more than 4 times in the last week often) cancel my bets for no apparent reason. Perfectly valid backs and lays. Yesterday, 3 back bets on O2.5 market, cancelled as soon as the first one was matched. No inplay suspension. Then today. O’Higgins lay the draw. Guess what? Cancelled before they went 1-0. No reason given. What is the point of trying to deal with an exchange which is either fraudulent or faulty? You can’t even take a bet in play because your ‘time in force’ function does not work. I’d love to hear your reasons…i.e. web interface reasons, why this is even a problem for you.