Hi Lulu40 Slade,
If your tax code ends in 'X' this is an emergency version of the code and will not backdate your allowances to the start of the year and would not generate a refund.
After the tax year has ended, (5 April 2023) we will receive end of year confirmation of your earnings and we will do a tax calculation and contact you if there is a refund due.
Or, once your employer provides you with your P60 details you can contact our helpline to update your earnings.
P45, P60 and P11D forms: workers' guide
Income Tax: general enquiries