Cash Crusaders in Carlton Centre

Cash Crusaders in Carlton Centre. I bought a powerbank which worked for 4 weeks and stopped working. When I took it back and ask for my money back they said they won't do that instead they will book it for repairs after 3 weeks they will call me. It took 2 months I went back to the shop nothing was done on the powerbank. I went back to the shop again they said the gonna book second time I was waiting for their call since last week. I'm sick and tired of going there and they have bad attitude.