Sale of damaged goods. Terrible customer service

I purchased a cellphone on the 20th of June. I brought the phone home and attempted to charge it and it wouldn't. I immediately tried calling them back but they had closed. I took it in the next day and they said they would to a swap out as it falls in the out of box failure period. I got a call a few days later saying that the charging pin was physically damaged and accused me of breaking it, which I obviously didn't. They did not test the phone in store to see if it was damaged. How was I to know that is was damaged when I left the store! They are even refusing to fix the phone! Their customer service is awful too. You have to keep calling them back to get information.