My League account chapion Bug.

My league account name is Blitzcrank B0T and my account is a NA account. l bought the chapion Tahm long time before, and l played it some time, but one mouth ago , l found l can't choose the Tahm chapion and the league store show l didn't bought this chapion. l try to find how to report this bug but just today l find l need creat this discussion to tell the bug. l don't want to spend one more 6300 ip to buy the chapion but l ready want to play him. Can the Riot solve this problem? Thank you very much.