You paid too little tax because you were a Scottish Taxpayer

Hey, HMRC had an old address in Scotland for me while I was living and working in London for the past 2 years. Tax rates are higher in Scotland. I called to update the address when I received the notification I owed money last week, guy said I wouldn't owe anything as we updated my tax code and address, and that HMRC may owe me money (I have been on a Scottish tax code while living and working in England). I logged in today and it says I still owe about 55% of the original amount, due to different reasons (non of which apply - i.e. changed jobs or had more than one job). is this a glitch that will fix itself or how should I fix this? I can't bear to call HMRC again. the first time I called, I waited 40 mins to speak to a human, after 1 minute of speaking she said "bear with me while if find out why your tax code has changed" and put me on mute (not hold), for over an hour. obviously hoping I would've hung up while she made her lunch or whatever (sounded like she was WFH), she hung up on me. then I called back to be in the waiting list for 30 minutes at which point I had to give up. then I spoke to the guy who told me I wouldn't owe anything after another 30 min phonecall.

Hi,
 

If our first calculation had a Scottish address, this may reduce the underpayment when a new is automatically done and you should receive this through the post. Once you have the new calculation, if you are still unsure if it is correct you should contact our helpline again: Income Tax: general enquiries  . Thank you.