MTN the worst customer service

I upgraded in July. The old phone was going to a family member. They are using a different carrier. When inserting their sim, the old phone sim locks. I phoned MTN, they gave instructions to unlock the phone. It did not work. I phoned them again and they told me I will need to go into a store. I went to the Brooklyn MTN store and they could not assist me and told me that the phone can't be unlocked and a MTN sim card will need to be used. I was not satisfied with this and phoned MTN again. I was put through to the network division and the lady assisted me and told me it would take 7 working days. After 7 working days we tried again to use the phone and it was still locked. I phoned again and was told that my query will be escalated and resolved within 24 - 48 hours. After 72 hours the issue was still not resolved. I phoned again and spoke too a lady who couldn't trace anything on the reference numbers after holding for a long period of time. I was transferred to another consultant and I asked to speak to a manager. She refused to transfer me to a manager. After checking the reference numbers, she confirmed that the first initial lady did not put through the correct information. I asked again to speak to a manager which she still refused to do. I then requested to lay a complaint and she brushed it off. She said that the technical department only properly processed the request yesterday the 7th of August and I should wait another 5 days for the phone to be unlocked. They are quick to take your money but their customer service is lacking. This is unacceptable service. A manager needs to call me and sort this out.