The rules clearly state that you can not solicit for rep or thanks, are you sure that you told him " Rep or thank me If I helped you "
If you said " If I helped you " then it's Ok, if you didn't, then you were breaking this rule : - No misusing/soliciting forum rewards, including on yourself. (However putting along the lines of "Rep/Thank me if I helped you" is acceptable) Which should get you a 3 day ban.