Bootloop Please Help! I just got this phone.

Hello, I have a BLU G71+ G0570WW the phone says /G0571WW is what the imei tag says. But anyways, I just got this phone and from the start, it was having some problems. Like it would get really really hot! Also, it would just shut off while I was in the middle of doing things out of nowhere. Well, my cousin said he could fix it and I agreed because he is really good at that sort of thing. So today he returned my phone but the battery is unhooked? I hook it back up and turn on the phone and it turns on vibrates turns off over and over. It won't let me get power + vol up or power + vol down menus. I asked him what he did to it. This is his response. 1. Unlocked bootloader 2. obtained rom for phone 3. ran fastboot commands (fastboot flash boot_a boot.img (enter) fastboot flash boot_b boot. img (enter) fastboot reboot) And the phone started with this bootloop thing. Please tell me there is a way that this can be fixed somehow!