It appears from your statements that at the time the local company was contracted for advertising, you were a representative of the company doing the contracting. The advertising didn't benefit you personally; it benefited the company. I would ignore them, but if you have documentation of having permission, keep it and in the future, whoever you work for, get documentation for permission for anything that the company pays out for on your request. You may want to seek legal counsel if they keep contacting you as it may constitute harassment. The contracted company may have to take your ex-company to court for payment and you could possible be named if it's your signature on the contracts. However, as I said you did not personally benefit, the company did and you were a representative of the company at the time the contract was signed. If this happens, seek counsel.