We were notified by a collection agency that we owed a specified amount to Cornerstone, however, we never received an invoice. we went to their office to find out what invoice they had sent out but when we got there (1). They had no proof to show that they sent an invoice. (2) the office manager had no invoice transaction process to show what was invoice and when and what was paid from unpaid. the office manager proceed to update the computer in my presence adding the times that she sent me invoices since nothing was on the system showing what date and time the invoices was sent. I challenged her to let me see what she was inputting in the computer and she became really annoyed and upset. I would suggest that folks double check what they are being billed for. The management offers no customer service. Be very careful, you'll also find that you are dealing with high school drop-outs at the front desk, as well as the management.