Shopmedionline Scammed me for $550.00

They sold me medication for $275 of google play cards....I should have listened to my gut and not done it.  The medicine was to deliver the next day.  Instead I get a call stating I had to upgrade because they were out of stock and they needed another $275, I stupidly did it....Then they call later saying the driver is on the way, but he has a cashiers check for the $550 that I have paid because they need payment to be made in 1 transaction. 

So they want me to give them another $550 in gift cards before they will send the driver.  I won't do it.  They won't let me cancel and give me my money back either.  They are rude, they call me names, they say that I am difficult.  It's definitely a scam.  I have been a fool......do NOT do it, if you're thinking about it, don't....you may as well set your money on fire and let it burn.