It is best if you contact an attorney and have her/him review the signed loan agreement. Payday loans are not illegal per se; however, there are strict rules in regard to them including statutory caps on the interest that can be implemented on the loan. An attorney can research whether it is a legitimate debt collection agency and whether they are abiding by the laws for collecting debts. A written demand for a detailed statement should be made and you can protest the amount that it being claimed. More details are needed to address what happened with your bank account.
Responses are for general information purposes only, and are based on the extremely limited facts given. A consultation with an attorney experienced in the area of law(s) indicated in the question is highly recommended. Information and advice given here should not be relied upon for any final action or decision, as the information is limited by its nature to the question asked and the fact(s) presented in that question. THIS RESPONSE DOES NOT CREATE AN ATTORNEY/CLIENT RELATIONSHIP, particularly considering that the names of the parties are unknown.