Samsung — switch off and switch again and again

hi i have Samsung galaxy grand prime. bought in Qatar Lulu hyper market. since 3rd days im complaining and went to service center 3 rd time and saying it will work now but when i start my mobile its repeated, got tired and i dont have much salary that i can buy another mobile, i really hate samsung product and service as well. its really annoying, what is the standerd if it is not working for even one week what kind of product you are selling. please contack: [protected]@yahoo.co.in