Achievement Quest problem

I reached fc champion in all 3 modes and joined a league. The quest is over, no more tasks, but the claim reward button is disabled. I worked hard for it, please let me claim the reward. 20k gems and 2 uniforms.

I contacted support through the app, they were unable to help (and told me some ridiculous things like try to reproduce on a new account, as if it's possible). They finally told me to write here.

See the attached screenshot. You can also see in your systems that this is the case I'm sure.

Please help