what do i do to get my phone to boot again?

my name is vincent and ive had the galaxy not 2 for about 8 months now. I noticed after a while that there was lag when i downloaded and played some games. I thought that if i factory reset the phone it would solve the problem so i powerd off my handset and turned on the bootloader menu and tried to wipe factory reset it but it said failed. i saw another option that said wipe format data and it said it would delete my BACKUPS and encryption so i did it (unkonwingly i deleted my os also). after that i factory reset it and it worked. i reboot the phone and the all it would do is stay on the glalxy not 2 screen and it would flash on and off sometimes. it seems i can only go into the bootloader and into downloading mode. please please please help me because its been two weeks and my phonee wont cut on.(etc details, it says no os when in bootloader, the phone is not on i terminated my contract, please can someone out there help me fix my phone, if you cant reach me here, contact me at my email(takeoffkidd@gmail.com) - thankyou