I can't gain or lose rank

[FallenAngelII]

Whether I win or lose, I get +0 rank, which is stuck at C5 at 3000/3000. I thought 3000/3000 looked really weird, but then when I went to play another game, from then on, my rank would remain unchanged whether I won or lost.

What's wrong with my rank and how do I fix it?

Edit: I changed from my Soul of Leixia CAS to Lexia and I manged to start getting rank again. Also, it seems I got all of the rank I should've gotten before because I got +500 rank. Random glitch? CAS-related?

 

[DrakeAldan]

You have to play C-ranked players or higher to rank up when at C5 or higher rank, all the way to A1.

When you max out the ranking bar you have to lose twice(?) to actually lose points.

 

[FallenAngelII]

You have to play C-ranked players or higher to rank up when at C5 or higher rank, all the way to A1.

When you max out the ranking bar you have to lose twice(?) to actually lose points.

I'm pretty sure I played two C5 ranked players (I set the search criteria to "Similar rank" and played two matches with that setting. One I know for sure was against a C5 player, the other I didn't check the rank on) without getting any rank out of it.

I also got +500 rank after the first match where my ranked finally moved. I'm thinking"Glitch" at this point.