Be aware of infinitec cell phone's

My mother bought a contract cellphone called advantage from the infinitec company,after 3months it started dysfunctioning: heat levels up, battery is swollen,back cover is protruding out due to swollen battery. So I took it to the company then they gave her a new one a month ago ...the very samething happened it heats , battery is swollen,it switches off when ever,the back cover is almost off...am just scared it will blow in her face (ears) any time soon and I don't know what to do in the mean time.