I am incredibly frustrated with this site

I make NFL bets every week but half of my bets don't go through, I just get an error message that says "failed to submit bet" with no explanation as to what I did wrong. I try to place the same bet again a few hours later and then it works. I don't know if this is a glitch or just a way for the casino to limit my action as I have been winning lately.
What happen to the bets which do not go through ? The money which you bet is credited back to your account ?
I think you should try to contact support if not already did so or maybe you need to check your own internet connection, if slow net is the reason for timeout.