Cadmium bearing silver solder is a banned substance.
Cocaine is a banned substance.
Anyone with an interest, buying or selling, in the latter would not advertise it via a public domain!
Such is the world today, the penalties for dealing with silver solder would probably be the more severe!
If you are experiencing any difficulty using the 55% cadmium free alloy review your brazing technique. see **LINK**
regards
keith