Faulty

I purchased an iPhone through MTN in October. The phone has 32gb of space. After taking a few pictures the phones storage reported full but everything on the phone did not add up to 32gb. I went and verified that with IStore in Gateway and they confirmed that it is faulty. I then returned to MTN and told them about the problem then decided to leave the phone with them after confirming with the consultant if I should remove the pass code and she said that there won't be a need for that I should just deactivate Find my iPhone. I left it on the 7th of January and I was told it would take 2-3 weeks for me to get it back. Yesterday 28th January 2020 I return to check on the progress of the phone and they tell me the phone was returned because of the pass code and what is more upsetting is that I was not called and they mentioned the phone was returned the previous week. I have never experienced anything this disrespectful. When I asked how long it will take if I leave it again they said 2-3 weeks which was going to be now more than a month and I would still be required to pay for a device that is with them. I decided to take my phone and I have to say this was the first and last time getting anything from MTN. I have used MTN for the past 10 years as my service provider and after this contract I will be done with them. I will fix the phone myself because I cannot deal with negligence.