Best fuel cards with the biggest discount?

Fleet one tried to auto withdraw $300 one day and transaction was refused due to low funds(factoring was running 2 days late unfortunately). Week later they withdrew $2000 normally. Third week all our cards and account were suddenly with out warning blocked! Trucks could not get any fuel and we could not see any fuel purchases and reports to prepare statements. After waiting 2 hours on hold since we didnt even know what was going on they asked me to wire them the money and wait untill it clears for 3 days or to request them to re run the auto pay and wait 10 days to for them to unblock me! I was also informed that we lost the line of credit :/ Their service became useless to us. Not to mention that there were no fuel discounts at all at FJ, Pilot, Loves, Petro in 2 months.
I truly believe that they were supposed to make our life and work easier and provide a good service. Stuff happens and why create a problem where there is no need for one? $50 Fee they charge should be enough. My advice is to avoid fleet one, we will be closing the account. We cant do business this way. <edited>