Mods? What mods, whats the point in that, im on a phone, android, whats the point of challenege if you are gonna cheat
You can contact support of you haven't violated any TOS. However i don't know how helpful they would be.
It may not be related to one week challenge. Does anyone else use your device or have you logged in on another player's device?
If you really are in the clean, keep trying.This is a very old post but hopefully it gives some insight.https://forums.playcontestofchampions.com/en/discussion/comment/82484/#Comment_82484 on the matter.