Collections Paid to delete letter from credit report

Good morning. An account went to collections, and I need to have a paid-to-delete letter. I've been trying to get this resolved for over a month. I moved from one location to another with the same service. I was told the bill from the previous home is being transferred to my house for payment. I'm in the process of getting a house, so my credit report was pulled, and a collection from True Accord via Comcast showed on my account. I could not understand why this happened when my service was transferred. I found out after further investigations that you set me up with a whole new account, which made no sense. Also, the bill was sent to my previous address, which I never received. Therefore, a collection was placed on my credit, which negatively affected my chances of closing on my house. I paid the bill and was told the credit would be removed from my account by Comcast/Xfinity by various agents. It is April 14, and my account still shows the collection. I spoke with a customer rep again this past Friday and was told I can receive a letter by visiting the Xfinity store. I went to the store and was told they don't do this. I'm being penalized again for a situation I did not create. And now, getting approved for my house is in jeopardy, although it says Paid. The fact that it's even there, although paid, still harms my credit because it's in collections. After all this, I'm still with Xfinity and have been a consumer for many years. Multiple representatives told me this would be removed, and nothing has happened. How can this be resolved?