Hi,
From the details that you have provided, it would appear that the class 1 National Insurance contributions that your employer deducted from your salary were correct and not available to be refunded.
This is because National Insurance contributions are calculated when you received your salary and you were, therefore, liable to pay them.
You may wish to obtain a State Pension Forecast via
Check your State Pension forecast which will detail your current and future entitlement to a UK State Pension.
Thank you.