Wi-Fi dont work

Hello, i have problem with my wifi in M4 Aqua. 1 week ago my wifi lossing signal but ok, i just must tap back cover and everythink works great. But today my wifi just dont wanna turn on. Please help, how repair that? Becouse now without internet i have just brick
I cant send that on guarantee becouse i must repair my jack :)
Sorry for english :D