A recent spate of lawsuits accuse 10 banks and a credit union of helping online payday lenders break usury laws by processing debt collection transactions. Payday lenders depend on those transfers, which are more reliable than debit and check transactions. The financial institutions are accused of violating federal anti-racketeering laws, federal banking regulations and industry standards and rules established by NACHA. The plaintiffs argue that the banks should have known that their customers were acting illegally and thus were helping them break the law.  Targeted financial institutions include large and small banks alike, from BMO Harris Bank to the North American Banking Co. in Roseville, Minn.