Cricket Wireless

I took my phone to store manager she says I need to file a complaint for my cricket phone.
I can't turn my phone off. There is no connection. My phone is completely dead.I have been with cricket over 6 month and I haven't had any problem until now. I used my phone for phone calls. I also used my phone for work and receive business call. I really need my wireless phone. The store manager could not do any more work. She tried all she could do. She says my phone is dead and I can't use it any more.