I had the same problem occurring on my 1 account. I would reset the password and it would still be wrong. I sent a few emails in to jagex and they replied back telling me to switch the password and then it worked. I think this could have something to do with a ban though because when I checked my bans and mutes I had 2 2 day bans one stayed and one was quashed. Both these showed the dates of right when this account problem started.