Capquest - Should I engage?

Hi,

After a little info regarding CapQuest. They have recently started harassing me via text and phone calls, I haven't answered any of them though and have been blocking the numbers.

As I haven't spoken to them I'm not sure what the debt is for, I have a few what I believe to be 'statute barred' debts as they are older than 6 years and are all showing as closed with zero balances on my credit file.

The only thing I can think it would be for is an old carphone warehouse account I had, this is less than 6 years old and has a balance of £172.

Recently after my accounts have closed my credit file has slowly but surely started improving and I have been getting accepted for small credit applications. I have a CC I spend small on every month and ensure it's paid off.

My question is should I engage with CapQuest? They have sent a letter but I returned it unopened.

Thanks, Andy