Old account help?!

Hi guys

Hoping someone can answer my question after trawling google for hours and nobody can help!!

I have checked my credit score on, experian, ClearScore and noddle and they all seem to report different things and scores, which I am aware can happen. Anyway, a few years ago when I was daft and young, I took out 2 lending stream loans which admittedly I have never paid back (although they never contacted me - I know not the point!). Some credit agencies show the accounts and some don't, however, when they are reported they are reported as "payments up to date" and never actually reported as defaulted!!!! Does this mean they will never come off my report as technically they have it defaulted? Also, would you pay them or wait until they come off my report? The are 4 year old accounts and they have never contacted me to pay.

Any help would be appreciated.

Thanks guys