Poor customer service

Poor customer service @ store level as well as call centre. Took up a data package 10G day plus 10G night plus double your data promo 10G day and 10G night. At the moment all we are receiving is the 10G instead of 20G as per the advert. According to the call centre the staff at the Tzaneen Lifestyle branch loaded it incorrectly. We have been struggling to get someone to assist us for the past 5 months now with no luck. The staff at the Tzaneen Lifestyle centre have a no care attitude, when we call the call centre we thought we have found someone to assist but we are still waiting for them to give us feedback, this is now going for the 3rd week and no one has phoned us back. It is extremely poor service especially as we have been customers for about 5 years. All we want is what we are paying for which seems to be a tall order for Mtn.