Poor service delivery

Its really disappointing how our consumers treats their customers,i bought a phone at Arkermans retail shop on account it was Rush phone and it stopped working on February the speaker died and freezing .When i took that phone and return it to Ackermans for repair, i took a slip with it but the slip it was erased and hard to see what was in that slip,so they say they cant help me and its not their faults .what surprisingly its how can an account holder they dont have a backup for all the purchases made ,how do they conduct audit if they dont have informations of their customers . Its really hard and difficult to buy a new phone especially at Arkermans retail company.all they care its your money when the problem occur,they distanced themselves