Poor customer service skills

I recently took out a contract for a Huawei modem with Cellc and after a week of use, it stopped working. I took it back to Cell c and they assured me that they would call me back in 7 working days to report on the progress of my device. After 7 days, I did not receive any calls so I called the store but the staff were constantly transferring my call to different staff members within the store and eventually a staff member, Emilia told me that I had been approved to receive a new device however there was no stock at the moment and they would call me as soon as stock arrived. Almost a week later I called the store again after receiving no phone calls to speak to the manager, but she was busy with another client and would call me back. After a day I did not receive a call so I called the store again to speak to the manager and they assured me that I would receive a call within 15 minutes. The manager, Yocumbo called me back and after 20 seconds of talking he cut the call and didn't bother to call me back. I have all my contracts with Cell c and this is the service I receive. The staff and manager need better customer service skills, as they are unfit to perform their job requirements