Product: Debt collection

To whom it may concern : I am writing to dispute the collection account listed on my credit report. The collection being reported by XXXX XXXX on behalf of XXXX XXXX is incorrect as evidenced by the supporting documentation Ive enclosed with this notification. Id also like to shed light on the unfair and deceptive trade practices XXXX is currently engaged in. 
My troubles began with XXXX back in XX/XX/XXXX. It was at this time that I had contacted XXXX to extend my internet service for a period of one year as my current contract had expired. Unbeknownst to me, rather than extend my existing term, the sales rep had created a new account. I was later informed by a XXXX employee, this was a common practice in order to achieve sales goal requirements ( I soon learned at the expense of unsuspecting consumers ). 
For the months of XX/XX/XXXX, XX/XX/XXXXand XX/XX/XXXX, as evidenced by my XXXX account printout from their website and my bank statements enclosed, they had double billed my account. They were direct billing my bank account as a requirement for services ( and as a promotion I was to receive a pre-paid XXXX card, which I never did receive ), so I had little control to stop these payments. When I informed them via phone in XX/XX/XXXX that this was occurring they said they would have it fixed. When it still hadnt been corrected by XX/XX/XXXX AND I began receiving collection calls from XXXX I became furious. It was necessary for me to take off work to go to their local office and get it corrected. 
Ultimately, it took me three days of missing work to finally get it corrected. XXXX had agreed to credit my account for the overbilling. This was shown as a credit on my account in the months of XX/XX/XXXX, XX/XX/XXXX, XX/XX/XXXX and the remainder of the credit in XX/XX/XXXX. This again is evidenced by the lack of billing for those months in the printout from my XXXX account. In XX/XX/XXXX, you can see where the normal billing then resumed. 
I was surprised to learn this account was being placed for collections with XXXX last month. After numerous discussions with several employees at XXXX, I was informed they wouldnt remove the collection and insisted I pay them an additional {$130.00} to remove it. This is having an extremely negative impact on my credit rating and ability to buy a home. I am asking for your help to remove this inaccurate information from my credit file. 
I was okay with the fact that I never received the promotional item promised. I was okay with the fact that the original monthly payment quoted ( see attached ) was not what I received. Where I must draw the line is when they are having a grossly negative impact in my ability to acquire credit. 
To summarize this injustice ; XXXX double billed me for services, never provided me with the promotional item I was supposed to receive, admitted they were wrong and credited my account, now have placed that same double billing for collections, listed it on my credit report and are refusing to remove it. I am appalled this Company can be allowed to stigmatize consumers credit by extorting them to pay monies not due using this tactic. Any help you can provide assisting me undo this wrongful act would be greatly appreciated.