Instead of paying them you should have gone to see a consumer attorney for advice. While it may be possible to get the money back if you have paid twice, you will now be forced to hire a lawyer which will cost money. You should factor this expense into your decision on whether to pursue recovery or not. You don't have CIVIL rights in this instance, however you may be able to get some money returned if you can show you paid twice.
Mr. Larkin is licensed to practice law in CA and is located in San Diego. His response here does not constitute legal advice and does not create an attorney/ client relationship. The response is in the form of legal education and is intended to provide general information about the matter in question. Many times the questioner may leave out details which would make the reply unsuitable. Mr. Larkin strongly advises the questioner to confer with an attorney in their own state to acquire more information about the specifics of their case.