iphone 4s has volume issues

hii...im sick of iphone 4s since i started using iphone 4s i have sounds problems,volume keeps going on off,i went to apple store they swapped it out with another phone ,after few days i have same issue with the new phone ,went back to the store swapped it out with another phone ,im just wondering when will be my next visit to the store to change the third phone

apple not meeting my expectations

😟 😟 😟