I sent in letter to withdraw form I-130 I filled for my husband due to some marital issues we were having. i have not received any confirmation letter

It may well be that there was nothing wrong with the format of your request.  Because of the large quantity of correspondence received by U.S.C.I.S., the average time to receive a response to a withdrawal request on a pending petition is generally 2 months.  To withdraw a pending petition, you should write to the Service Center that is holding the petition, and simply request that your petition be withdrawn giving your names and the USCIS case number.  You can also attach a copy of the receipt notice from the agency. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.