@HMRCcustomers just tried calling ACAS and they specifically say they can't help with issues relating to P60s so I guess I will have to keep calling HMRC until I don't get hung up on...
@HMRCcustomers They have shared their record of the PAYE totals they have for me and it looks like there were 3 months from External Payroll Bureau and the rest of the year was internal with Xero Payroll
@HMRCcustomers They did report it, and they say it was correct, my P60 is correct, but the amount that is on my HMRC account is wrong. HMRC say there was an error in RTI and my prev employer must fix, but I have just heard back from the employer that the error was not with them