Complaint Review: Prepaid Mobile

Prepaid mobile - 488, fashion ave, NY (2016)

I bought a prepaid sim card of Simple Mobile in this store (02/21) and I paid the value of ten dollars in cash, and the sim card would be deactivated in 02/28.
The problem starts when the seller said that he need my credit card to stipulate a limit in case I need buy new credits. This limit was in the value of 249,99 dollars and the seller makes more than clear that this values WOULDN'T be credit in card.
In addition, how I'm brazilian, the seller explained in spanish and used the translation for portuguese to make the things more clear because I was insecure in use my credit card.
Arriving in Brazil, I had the bad surprise of the value of 249,99 dollars in my credit card.
I tried contact with Simple Mobile to understand this value, and the support said that I didn't buy anything; that don't control of my credit card.
Now I'm fighting with the bank to try cancel this value. The bank needs a document to prove that the value were cancelled. Now, how I'll have this document if a can't contact the seller? If I call and nobody aswer? If don't exist other contact?
I just want an answer of the seller, my document and my refund!

In addition, when I contacted the Simple Mobile they said that my sim card were active yet.

It is impossible to contact with this seller!! I tried everything: email, telephone, text...
I found a lot of other customers that suffered the same situation with Prepaid Mobile and with bigger values than mine.
I just want this 249,99 cancelled for the company of my credit card be able give my money back!!!