Falling to respond to phones after taking money for sending samples

I put a query on tradekey.com for white oak coal suppliers but needed companies to send me samples. Amoco trading representative by name of Vander Johnson (with west African accent on the phone) sent me a response. He quoted 500 rands to send samples from PE. Then next day he came back saying the price is double because DHL said they charge double for flammable samples (doubtful). I sent him another 500 ZAR on Thursday 7 September. Now he doesnt repsond my whatsapps and calls. The conpany is genuinely registered on CPIC website.