Can't access my wordpress.

Hi
I have a few different wordpress sites, one of which I set up to try different themes etc without it being live, problem is I can’t access it.
Tried to retrieve my password by entering my email and what I thought was my username but neither are known to www.remarpro.com.
I already looked at the support threads for advice, but the answers given all involve stuff which is way over my head. Is there any way of finding a solution for this?
Thank you.