FRAUD

i have been dealing with a lady that gave me this address, basically I sold a cellphone to her and she asked me to deliver the phone to 7 Pascoe Ave in Kempton park, the phone was delivered I received an email from paypal to say that the money has been paid from Maria Snyman her son is Eric Snyman now she comes and say she paid R 4000.00 more and needs that money back before i can get my money for the phone, I NEVER RECEIVED ANYTHING please if you guys are dealing with DPM Hydraulics or Maria Snyman be VERY CAREFUL