I`ve been trying to get a paid up letter

I have settled my account with Telkom Mobile in the beginning of September I phoned the call center on 06/09/2017 to log a case for a paid up letter and I was told that it takes up to 72 working hours Well the 72 working hours or 9 days have passed I phoned on 18/09/2017 and the consultant assured me that I will receive the letter with in the same day or in the morning but it would not take more than 24 hours 24 hours have passed no letter I phoned again the next consultant also assured me that I will receive a letter but haven't received anything yet so today 20/09/2017 I phoned the call center again and this time the lady I spoke sang the exact same tune as every other agent I have spoken to firstly they say your call was escalated to the back office they will send you the paid up letter within 24 hours please be patient I cannot be patient anymore as this is starting to become frustrating