Difficult to sort out problems

Hi I went for a renewal of my cellphone contracts about to months ago. My Wife uses the second phone and I phoned(135) and spoke to a person regarding my phone having a credit limit of R290. I asked the person to please recheck as I have asked them to increase this. She now confirmed with me that it was asked on the 17/09/2018 but credit did not allow it to be done. In the first instance nobody confirmed this with me. In the next instance my income is above R500 000 year how do I only qualify for R290 credit limit not reviewable for 3 months??? I am very unhappy with the service and no one being able to explain or help me. I ask this to be sorted urgently I submitted a formal complaint on the 16th of October just to get a ref" Formal complaint on number [# ********** 2]" but no reply on my problem. Unbelievable a big company with no formal complaint procedure and follow ups.