HMRC Think I have two employments - Taxed double

Hi, In November 2023 I have changed jobs. I have handed in my P45 to my new employer, was on emergency tax code for two months and then everything was fine as it switches back to my normal tax code. However, next month it switches back to emergency tax code and my employer is saying I need to contact HMRC to sort this out. Logging into my online tax code account it shows that I am still employed at my old job and my new one and Im currently getting taxed double and I can not afford this. I have tried to contact HMRC in every way possible but to no avail. Everytime I call them I just get ''We are really busy, call us back latter.'' and the phone just hangs up. I have been now getting double taxed for 6 months and I still cant get through to HMRC. Could anyone please help me and tell me is there any other way to contact them? Thanks in advance Kind regards.

Hi

I am sorry you have not been able to contact HMRC but to review your tax code we will need to access your record.
Contact details for HMRC at Income Tax: general enquiries.
If over paid for the 2023/24 tax year which ended 5 April 2024 then once HMRC receive your PAYE figures we will review your record and a calculation will be issued with the details and how to claim. 

Thank you