Shaun were you partially matched?
If so this can cause you not to get set.
eg. If you have a bet open for a liability of $35 and have "take SP " ticked and a part of it gets matched which brings the liability that is left to under $30, this will then not be matched as the liability is < $30.
If you get my drift.

Na these are straight back bets placed at the current back price, i can make a change and set it so if my bet is not taken within 5 seconds it gets submitted again as a safe guard but not sure why this is happening, as i said these are small amounts most under $10.

I would use another betting agency but because i am betting with a saver if the price id below $3 i need to use this bot and betfair.

Shaun have you checked your system time? Have you recently updated your bot software? What do your bots logs say?

As mentioned previously you'll often get matched for odd amounts when a late scratching accidently triggers bots to accept prices that are in temporary flux due to the market being reset.