Failure to respond as promised within time frame given

I lodged a complaint via the correct channels and have been patient for 48hours now. When I lodged the complaint on Saturday 2nd December, I was told by the customer service agent that I would receive a PHONE CALL back by Monday 4th December, that did not happen. I then called at 4.30pm 4th December, held on, was told I would get a call back, phoned at around 5.30pm and was told the manager was not available and he knocks off at 6pm. Tuesday 5th December at around 10am receive an email my complained has been lodged......very vaguely stating i would be contacted in due course.....how much longer must i wait? I am going to lose my 10 day return policy time frame at the rate this is going. I am already beyond livid that the item I purchased was falsely advertised as something it is not, and I am therefore not able to use it for the main reason I bought it for and I therefore complained about that but now I need to complain on this public platform as to get some sort of service. I am in the same industry as this online store, and this is absolutely unacceptable customer service. This is completely unacceptable.