I have just opened up a check cashing business and had lost $5,000.00 for bad checks.pls advice!!?

getting the license cost a lot of effort and money thus, i don't want to stop. i need your legal advice or any opinion if you have this kind of business.. how will i be able to avoid bad checks? i have tried using verification machines but still, it didn't stop. some idiots used real accounts , real checks but not issued for their names thus, i don't get reimbursed for cashing. i even asked for social sec numbers, driver's license and thumb prints.. what will i do? pls advice.. thanks!!!