How to get help resolving an overdue refund?

I claimed a refund on overpaid tax and received a letter four weeks ago promising me that the money would be transferred into my bank account, but as of today I have still not received anything. Neither the phone line nor the digital assistant provide any help, as they always direct me towards making a new claim or to the 'when will I hear from you' page (but I have already heard from you in writing, but just don't have the money). Where has my refund gone? Or should I just be more patient? And how do I get through to someone who can actually help resolve this?

Hi 

We will need to access your record to check on the repayment. You can contact HMRC at Income Tax: general enquiries 

Thank you