How Long Will One Reversed Payment Show On My Credit File For

In June I had a reversed payment for the first time in 20 years with HSBC.My account was over limits for around 21 days.In August when I'd hoped to move to new mortgage deal with my mortgage lender Halifax even though all the mortgage payments had been made I was prevented moving forward by my HSBC account showing up on my credit file as not up to date despite the fact that it was back within the overdraft limit.My account has been within its overdraft limit August, September and currently(it's now early October).All DDs and SO's met, no missed payments, I've always had a good relationship with Hsbc with whom I've banked for 20 years. When will my file be updated?this is making me quite ill, if the reversed payment was on 21st June would it not be taken off my file now,3 months later?This is totally preventing me from being able to consolidate my remaining loans onto my mortgage, and save a great deal of money, lift myself out of any debts and open a savings account for the future. Please help