Incorrectly sent to collections - A collection report ruined my credit score and it is making me lose my earnest money of $25000.

I had Xfinity internet when I was living in Virginia. I got Xfinity mobile as a bundle with the Xfinity internet. The plan was based on data and it was $12.00/1Gb. So, it means if you would not use mobile data in a month, then the bill would be only 12 dollars. I had the plan in 2020 and I moved from VA to NM in July 2020 for a job. In Dec. 2020 I left the country and got back in April 2021. Based on the plan I had at that time, if I would not use mobile data, then the mobile bill would be 12.00 dollars. When I came back to the country, I went to Oregon to start a new job and at that moment my company gave me a new phone with a new phone number. So, I used it and I haven't used Xfinity mobile since Dec. 2020. However, Xfinity kept charging me with charges much higher than the $12.00 per month and all of them had been paid through auto-payment which was set for my account at that time. In April 2021, I called Xfinity and asked them to cancel my plan and over the phone they confirmed that my Xfinity mobile plan was canceled; however it had never been canceled. It seems, they never stopped charging me. They had been sending bills to my Virginia address which I did not have even access to at that moment (since I was in Oregon). Also, Xfinity had been sending my bills to my student email which I no longer have access to since the end of 2020. In addition to these, I did not have access to the Xfinity mobile phone number since I had already canceled it. So it means there was no way to communicate and I thought the plan was canceled, although it was not. They charged me for a few months; however, there has been no payment for those months since I was not getting the notice regarding Xfinity bills.

Recently, I applied for a mortgage loan and my credit score was decent. there was no impact on my credit report from anywhere. However, a few days ago, my lender ran my credit score for the final approval of the mortgage loan and they figured out that there is a collection report against me from CCL. I called Xfinity right away, and they told me that I owe $318.67 to Xfinity Mobile. I talked to a lot of people over the phone and through chats. My lender told me that if I can get a deletion letter from Xfinity, they can do the fast pull on my credit score and they can lend me money; otherwise, I will have to forget about it. In my phone calls and chats with Xfinity I was told that in order to delete this collection, I need to pay for it first and then Xfinity will send a letter to the collection agency and a deletion letter to the credit bureau. I have all my text messages with Xfinity and in my conversation with them, they clearly confirmed (written in chats) that they were going to remove this collection. Also, I talked to level 2 specialists and they said that this collection would be removed in 24-48 hours. They said that they were going to send an email to the credit bureau and let them know that this collection should be removed.