I was diamond in 3v3 last season, but it says my highest rank last season was plat?????

So i became diamond v in 3v3, and plat in solo q, so at the end of the season it said i my highest rank was diamond 1 with was false, but whatever lel. Then today i got downgraded twice. To diamond v, with was what i should have been given so i was cool about it. Then when i log on 3-4 hours later my account got downvoted to plat v as highest rank witch is pretty anoying... But when i want to flex my diamond border in normals and so it fucking shows my worst rank border.. Gold.. Like what is wrong?