Mortgage application rejected because of O2

[MissSunshine]

I was an 02 customer for many years and never had a problem with my phone. I always paid my bill on time and never had to contact 02. Earlier in the year I (now regretfully) switched from 02 to another network provider. I didn't think anything until one day I got a letter, completely out of the blue, from a debt collection company, Moorcroft Debt Recovery Limited, asking for £30, I didnt know I owed. I was mortified as I have never missed a payment for anything so on receipt of the letter rang up paid this off immediately.  

I didn't think about this again until yesterday. I am in the process of remortgaging and my credit check came back fine and our mortgage was being approved in principle. I have been told that my mortgage application has been declined as there was a problem relating to a phone contract in my husbands name. Naturally my husband paid for and did an enhanced credit check - this came back fine with no problems. Confused, I did the same and everything I have paid for over the last few years is fine and ticked in green....and then it shows that in April there was an "arrangement to pay" note on my account but that the account has been settled and closed. 

Completely shocked and upset I immediately went into my town's 02 store. I was very upset and stressed and I spoke to someone who was brilliant. She was concerned and confused why this would be on my account when I'd paid it off and closed the account. More importantly she asked me about the "three reminder letters you should have got". I never had any communication from 02 after I closed my account, the only and first correspondence I got was the letter from the debt management company.

I am utterly meticulous when it comes to paying bills, I put everything in a sectioned filing cabinet and I can categorically say wholeheartedly if I'd have got a reminder letter through the post saying that I owed money I would have paid it off in full immediately. 

Anyway...... what can I do? Can anyone help or advice. I am so upset and stressed out. I've had a mortgage for over 10 years, I have a very good job and more importantly,  can this be rectified?

Thanks if you have read this far!!

[madasaf1sh]

@MissSunshine 

Your first mistake was to not query it with Moorcroft, as you paying it off is admission of the debt, you should have queried it at the time..

After 7 days any letter is deemed to have been delivered by Royal Mail, you would have to prove Royal Mail where negligent in failing to deliver the letter..

As such the CRA's. Moorcroft and O2 wont remove it from your credit report, as you have admitted liability.

What you are best doing is asking the CRA's to put a notice on your credit file, explaining the situation.