Rock River Partners firm. David Stevens Charged me 4200 for a service and not completed my services and now demanding 6720 dollars more I'm out 4200

I was contacted by Rock River Partners in December 2017. Rock River offered me to re-sale my Mexico vacation property for a great offer.  Rock River asked me to pay 4200 dollars for a percentage that the vacation company contact stated.   I agree and proceeded to transfer 4200 dollars in to a Mexican bank and Rock River guaranteed and promised me in writing I will receive my pay out within 48-72 hours upon them receiving the wire transfer.

 They collected the transfer and notified me days oater stating that the Mexican government Placed a lean on the propertfor a tax of 16%. Rock Rmere order me to pay the 16 % lean otherwise I wouldn't get paid.  I began to question many more things and suspect the company at this moment I'm currently out 4200 dollars and the company won't refund my money.