All American Dream Wheels Issue

About 3 months ago I had custom skates built, Riedell 297's, Arius Plates and Suregrip All American Dream Wheels with the aluminum hubs. I mostly rhythm skate and now those wheels are moving on out of the hubs. Has anyone had this issue? If so, what did you do?

I am planning to put Red Loctite between the wheel and hub or some type of glue.

Another thing, I lost 1 of the cotter pins on one of the wheels and need to replace it. Does anyone know what size I need?

Thanks.