It's a scam
1. ONLY a scammer asks for Western Union payments
2. NO breeder would ever sell you a capuchin until they had done a site visit to your home to verify you have the appropriate sized outdoor enclosure for your jurisdiction AND that you hold an exotic animal ownership license. Most will also require you to have first taken a primate handling class
3. A baby capuchin costs Minimum $5000 for a male and $10,000 for a female - you won't find them for less from any legitimate breeder
4. Most airlines WILL NOT ship primates. You have to pick it up in person and drive it home
5. You will rarely meet anyone with a pet capuchin more than 5 years old, even though they can live to 45, because most turn aggressive and violent at this age when they are reaching sexual maturity. They are either out down or put into primate sanctuaries if one has space
6. Seeing pictures means nothing. There are hundreds of thousands of pictures of capuchins online anyone could copy. Speaking on the phone means nothing. Any scammer can give a fake name, buy a cheap pay as you go burner phone in cash so they can't be traced, and collect money from 10 different victims and not get caught
7. If the scammer claims to be in another country it's definitely a scam as only zoos can ship animals internationally. Private owners cannot. Even if there was a monkey and it somehow got smuggled onto the plane and survived, it would be immediately put to sleep upon arrival as animals from abroad carry too many diseases not found among local animals that could create a dangerous epidemic as local animals have no antibodies against these diseases
If you do not live in a state where monkey ownership is allowed (they are banned in more than half of states now) and do not have an exotic animal license issued by your state department of wildlife, nobody will sell you a capuchin. They can't or they would be breaking the law