MTN bundles are a ****!!

I have constant billing issues when using MTN bundles. The 2 most common being that their is almost always a discrepancy between what MTN determine that I have used on a particular bundle and what the data usage figures on my phone show..it averages on around 100mb and after several pointless queries with MTN customer care, I have resigned myself to just losing out everytime. The most frustrating issue though is one that is happening to me right now..and has happened before. I purchased a Summer Suprise daily deal( honestly quite good as you get a lot of data for your rand). After using up around 75% of the data available on it, I decided to go ahead and purchase my weekly 1GB bundle as ( happened to me quite often, I end up using up airtime once the bundle has been depleted. I receive the warning from MTN about 5 mins after the damage has been done, which is pretty pointless) So after using another 300mb or so of data, I check my balances on the app to see how much is left on the daily bundle - only to find that my weekly bundle is being depleted and the daily bundle is not. The last time I contacted MTN about this, I was given some line of **** about the system defaulting to the most recently added bundle and essentially as a result, I was *****ed So going forward, I would have to try and gamble on the timing of when the daily bundle was depleted and only then should I add the weekly bundle. Yeah..I tried this..its not possible..because your alert only comes through after the fact. And I end up paying out of bundle data rates of r2/mb. This seems like a cleverly constructed method to recoup the loss incurrred by offering the low price daily deal. Either way, I have purchased a bundle that MTN is not allowing me to use. Surely that is *******..let alone really poor customer service?