Indoy Jones,
Since the link between you and this Rufino Ayson is your friend Dominic, I think he can give you more solid information on how he gets your cell phone number. These are some probabilities you will need to consider:
1. Your friend Dominic knows Rufino ayson.
2. Dominic mentioned to "someone" about you as a gold buyer, and this someone mentioned it to Rufino Ayson.
3. If your friend Dominic do not know this Rufino Ayson, a "group of people" have a listing of "gold buyers" or "connected to gold buying" and chose your name randomly.
4. If this Ayson is stranger to you and to Dominic, then be careful, because they know who you are, what you do, and how much you worth.
In my opinion, there are no LEGITIMATE AU in the market AT PRESENT, what are circulating nowadays are all fake AU.
Angel_09