moneyback.mx Have been trying to get my tax refund from purchase done at Dimonds Inter. in 2015 cozumel Internet

purchased earrings at diamond international on3/5/15 while in cozumel. was told about the tax refund and they made copies of my passport and flight info. i waited and waited and nothing so contacted moneyback.mx and told they have no record of this and to contact diamonds inter. guess what they have no record either so when we were back this feb. i took everything back to diamonds inter. and they don't know what happened so they make copies all over again and i'm still waiting. think this is a big scam on diamond inter. part as part of their sales pitch.don't fall for it people