Question regarding acount

Hello, r/Runescape.

I had an account that I played a lot when I was younger (read 5-6 years ago), then quit for quite awhile. Last year, I bought a month membership to try it out again and my account still existed. However, now when I try to log in, it says my account info is incorrect. I looked my character up in the hiscores, and it says that it doesn't exist. The username is Sylvermonkey, and it was like a level 90-something. I guess I don't really care if I get it back or not, I was just curious what's changed in the past year, and what my character had in the bank. Is it common to delete characters for inactivity?