Generalised Anxiety Disorder and Benefits

Hi there-I’m new to this site and have spent a couple of hours getting used to it and am well impressed!
In addition to restricted mobility due to ankle injury and surgery, I’ve also had a couple of DVTs both of which were accompanied by Pulmonary Embolisms which have caused respiratory problems . Things aren’t great but I’ve lost weight and have improved my nutrition and I know this helps a lot of physical symptoms. My main issue at present is Generalised Anxiety; the anxiety is accompanied by OCD so when I focus on an issue in my life that causes anxiety it is exascerbated by the OCD. 
Surprisingly, my recurrent anxiety at present is over finances. I’m in receipt of Universal Credit and in limited capability for work and work-related activity. Although I can access the online account and journal OK, I find Universal Credit to be a stressful benefit to be on, mainly because it’s a mixture of 6 legacy benefits. The staff who send messages via the online journal are respectful and I think do their jobs to the best of their abilities, but it’s the actual Universal Credit IT system that scares me. 

Anyway, the question I wanted to ask is- “Has anyone had problems receiving National Insurance Credits when claiming Universal Credit? I have had a continuous claim for Universal Credit and should have been awarded NI Credits all the while. However, they have not been credited to me and I am confused about how to proceed. The HMRC say it’s a DWP error; the DWP say it’s HMRC responsibility. If anyone has any advice on what to do-even if it means officially complaining to DWP and/or HMRC about the error then that’s fine. I’d just really appreciate any info or signposting as it’s a slightly tricky one.

Many Thanks and Stay Safe

PS-I had the first dose of Pfizer vaccine 13 days ago and it was absolutely fine-a little tired afterwards but very similar to flu vaccine.