HFC/Beneficial reported late payments on my credit report that are untrue mobile, Alabama

I made a payment at Western Unions(which is an authorized payment, center for HFC) quick collect services on 08/04/2012 to HFC/beneficial.  In oct 2012 after reviewing my credit report, I discover, my credit report has two delinquent  30 day late payments on it for the months of august and september of 2012. I contacted HFC and Western Union on several different occasions and spoke with several different operator and customer service personnel. Western Union confirmed payment with the correct account number.

I faxed a copy of the Western Unions receipt to beneficial/hfc, they won't even call me back or email me, all they say is , " we recieved the fax or our files show the fax you sent is in the research department.  It's simple, I've been with this company for greater than 5 years with no late payments, they have a faxed copy of the receipt of payment from Western Union confirming the transaction was complete  but they have made no effort to contact me or correct my credit report.  If they do this to me, just think what they would do to you.  By the way, this "Valued customer" was inquiring about my credit score because i was planning to purchase a home, which is still going to happen but this certainly has had a significant impact on my credit score.   I will not stop until this matter is resolved.