Twitter and Facebook problem?

[Amber]

Okay so on twitter AND facebook it won't let me reply/favorite/like/etc. anything this one certain person writes. Only that one person.... I thought my stepmom might have been on my account and blocked then but they're not on my blocked list... It will let me reply or whatever to everyone elses stuff just not theirs, and I know they didn't block me or anything... it lets me see their account but as soon as I click on it it brings me back to the home page
Anyone might know why?

[Mizanur]

but why?