I have avast cleanup. paid for a year sub which doesnt expire till 17/3 /2017 and I cant access it nor down load the license to use it ,
when I do a virus scan it says these problems need cleaning so then wants me to pay again so how do I do it … any help ? 
A malware scan has nothing to do with what CleanUp does.
They are two different things.
How to activate CleanUp can be found in the FAQ.
https://www.avast.com/faq.php?article=AVKB205