UC - worst case - what happens when? mitigations.

I'm 63, unable to work, receiving PIP and seeking Universal Credit. My savings are chiefly in pensions built up over decades. Cancer, psychiatric illness and addiction (now in recovery) have left me heavily indebted. (v big HMRC debt). I've repaid a personal loan, withdrawn £4,000 for living costs (max tax free from pension) and transferred balance money into a pension to control compulsive spending. I bet I breached the 16k cap - but it happened because i was seriously ill. I ended my UC in Jan as their intensive questions made me more ill; I am out of cash now so can I make a UC claim? Worst case - they bring claim. I have no assets outside pension and huge debts and I just want to get well - NHS is not quick so UC will tide me over. I have a carer. I cant open the post so I am very slow and over time I think I will be able to get on my feet but what should I do this year? With thanks. Tony