When you don’t pay a debt on time, the original creditor (such as a credit card company) will probably try to collect the debt itself for several months, usually by sending you multiple copies of your bill marked as “past due” or by numerous phone calls. After that time, they may assign your debt to an outside firm, either a collection agency such as Alliance One or EIS Collections or possibly a law firm, who will continue to contact you through mail or phone calls for a number of months.