They could not give me a cause. I did try out the floss they replaced it with. It’s inferior. It feels plastic. I’ll in no way use it. I attempted so many various styles of floss and Dr. Tungs is definitely the winner fingers down. I applied it as directed https://beckettinmsv.uzblog.net/dentitox-pro-supplement-things-to-know-before-you-buy-41185190