Hi, Naturally looking for some guidance, the details are as follows: I currently have a repayment plan with HMRC for overpayment, which i disputed via TC248 and a further appeal, which HMRC failed to acknowledge i was going around in circles and just agreed a repayment plan. I have received a letter from Pastdue for a further overpayment, this is the first i had heard about this as i would have definitely challenged this all the way to court. One overpayment, i can stomach, but further miscalculations are frankly disgusting and damn right unprofessional from a systems perspective. I contacted HMRC and asked why they had not contacted me, they responded that they had a sent a letter which i clearly had not received, they advised to take the issue up with Royal Mail, which is laughable really. Ironically i was calm and polite on the phone and the lady said i was talking to her aggressively, which was utterly pathetic and frankly untrue to be honest. She refused to take full payment off me and said i had to deal with Pastdue, i explained i owe HMRC the money and wanted to pay and have no dealing with some half baked collection agency, she then promptly cut me off. So now i have a sum of £1700 owed which i can pay right away and i have submitted SAR. It's a matter of principal that i have not been able to exercise any rights that i may have and have been unfairly denied the ability to make payment or to enquire further as to how the overpayment was calculated. Will this affect my credit rating, can pastdue send bailiffs, do i have an amount of time, do i have to acknowledge anyone? Where do i go from here? and thank you for taking the time to read my post.