i received a collection notice dated XX/XX/2015 back the beginning of XXXX 2015. They demanded payment on behalf of a company by the name of XXXX XXXX XXXX. I have never heard of this company, so on XXXX XXXX, 2015 I sent a written request for validation to ACS, in the return envelope they provided, and the first class postage I provided. On XX/XX/2015 I received another demand for payment, by they have yet to honor my request for validation of the debt they are attempting to collect.