Then items they have drawn off the $500 (and it could be quite a few) come through and BAM snowballing of NSF fees and overdraft fees that can easily run into the hundreds.
Easy solution: use a credit card and pay it off every month. It should be pretty simple to ensure that you have enough available funds (i.e. cleared checks) in your business account to cover a CC bill once a month. Presto, no snowballing NSF fees, the only thing you would need to recoup is the initial bounced check fee.
Is there a specific reason you're using a debit card instead of a credit card?
Had a mom accidentally write me a check off a closed account. The funds had already been appropriated. What comes in goes out, no profit on dedicated funds...I was left with a bevey of NSF charges to the tune of over $1800!
I'm sorry that happened, but that speaks more to an account management process in need of improvement. Incoming checks aren't your money until they clear, if you keep that in mind you will never again trigger NSF fees on your end.