Breach of contract

I bought a new cellphone and when I arrived at home I picked up that the settings icon -undersecurity was not working went back to the store regarding the matter , arrived at store around 1:30 - until almost 18:00 .. the employees then agreed after trying to fixed the cell phone ( through the call centers as well as mtn outlets as well as the Samsung specialist) they then agree that I can come tomorrow to fetch a new phone , I even told that that I work very far from home but they pleaded that I come to receive a new phone . To my surprise when I got here it was a different story bear in mind how much money I used to get hear even not being able to go tho work .. now they r telling me stories , n that ****es me off???. Poor customer service n they can’t even acknowledge their mistake .