Bad service

My husband and I we brought Nokia phones at springs mall 28/01/2018 both phones gave us problems over hurting. Freezing as well not connecting to network. due to our work time couldn't bring back the phone immediately, after 3weeks we went back to the shop requested to exchange phones buy another, cause we won't be able to come back every time when we have issues , which they refused it's not allowed after a week but the will send the phone to brand so they can fix it . Now my problem is the services is so bad that no follow up calls made we had to go there and still Nothing , they keep say will call you till today no call still waiting we want our cash back no longer interested in any phone the sell. Please help us