Iphone bought unlocked and blocked (IMEI) by Sprint

My name is Bruno and I am from outside US and bought an Iphone 7 at 5th anevue store on 01/24/2019, I bought a free contract device (unlocked) to use in my country - Brazil were I live.

I´m using this device since february/2019 with a local mobile chip here in Brazil. But today 8th of may, my signal stoped to work. I contacted the apple´s brazil suport that discovered the IMEI has been blocked by Sprint (i dont know how).

So, I tried to contact Sprint and according to then, in last april my device was actived in a Sprint account in US and deactived on 5/5/2019 by fraud. And becouse of that I had my phone´s IMEI blocked. But my device was bought in 1/24/2019 and has been used here in Brazil since february. How my device was linked with a Sprint account?

I have the purchase invoive that proof that I bought the iphone. 

Please I need to have my iphone IMEI unblocked, becouse I´m sure that was a mistake.

Last time i talked to sprint they tell me that will be possible to unblock the imei if apple contact them and confirm that iphone was bought in january, and the phone could be unlock.