Santander credit card they keep adding interest after saying they would not - compensation/complaint help needed

[Lady_wise]

 il try keep this brief. 

 

I have various creditors, 

All but one has been fine. 

 

I have a disguised mental health condition that effects my capacity to manage money, I can be impulsive and spend money when I shouldn't I have no ability to stop myself doing it. I have several conditions all of which I have proof of but they don't request to see it even when offered. I'm on medication for it. 

 

Iv asked another creditor to write off the Balance because of it but they have refused sending me generic letters saying that they have looked at the information provided considered all evidence of which was my letter from my doctor outlining my conditions. I feel that they haven't even looked at it but that's another matter. But they have stopped the interest. 

 

 

Santander , I have a credit card with them and all has been fine up until now, (i.e- always paid well above minimum) but then i ran into difficulties as i had just spent way to much, I'm currently in plan with them and they agreed to stop the interest for 3 months however every month im having to call them as they keep applying interest and

I'm having to call up everytime to get it rectified. Which im fed up of doing and is causing me more anxiety and stress.

 

Can you please advise me on if I have grounds to complain.

As I feel in the grand scheme of things all they have looked at is affordability and not capacity.

 

Please don't judge me. 

My mental health condition is complex.