who is responsible for displayed prices at their platform? they or you? why should they compare their prices with those on another platform? were you now to trade with prices other than those on the platform where you can your account? how stupid will that be? of course you will use their prices and if for some technical mess up on their part you made a decent profit, they should pay up. for when those same prices made you lose, they did not refund your loss did they?
when they are aware of technical issues they should suspend trading on the platform till it is resolved, so they became aware of technical slippage in prices ONLY AFTER you made a profit? no sense at all. you are in the clear... they obviously are up to no good.