To investigate the authenticity of injectable filler, you can contact Allergan (the company that makes Juvederm), and have them investigate your case. They should have a record of your lot number and the purchaser. The FDA can also investigate these cases, but I think Allergan is a good start.
Contact Allergan and discuss your concerns with them.
Contact Allergan and discuss your concerns with them. If you received a product that was not Juvederm the clinic will most likely be investigated.