Tax refund from PPI repayment

Hello I received several PPI repayments a couple of years ago and i became aware that i could reclaim the tax on the refund. I originally submitted a R40 form but was informed that due to claiming child benefit previously and therefore sending self assessment form i would need to make changes and re submit the form for that year which i did . I was also asked to send original copies of my PPI repayments to HMRC which i did and was also asked how i would like to receive payment, it is now getting on for six months and i have not heard back from HMRC or received any payment. I have tried several times to contact HMRC by phone , online, and sent a written letter but have had no luck, my HMRC online account shows the forms but just has the word completed next to it but nothing else. I am now at a loss of what i should do next and was wondering if making a complaint would help speed things up, any advice would be gratefully received. Many thanks Steve

Hi Steve Coates,
We are sorry for the delay in processing your repayment claim.
For an update on the progress of your claim, you can contact us by webchat here:
Self Assessment: general enquiries.
If you'd like to complain about the service you've received, you can do so here:
Complain about HMRC 
Thank you