MTN clearly

I have been a loyal client of MTN for over 20 years. It has taken MTN more than a year to sort out, despite visits to their offices, multiple phone calls and sms's to the apparent management to no avail. No one in MTN can or wants to assist me. I have an electrical company which receives +/- 100 calls daily. I often have to deliver services abroad and when doing so, I need my RSA customers to still be able to contact my team. The predicament is actually, quite a simple one... I need a call divert to VOICEMAIL activated when I am travelling abroad in order for my RSA customers to know who to contact in my absence. I have 'activated' the 'service' over 6x times since 2014. Every time I travel, the divert is not activated, resulting in me having to answer the call as I run the risk of losing the potential business. Now what is adding to this dilemma is that every time this exercise is costing me thousands in Rands in MTN Roaming Fees for a service which they could not deliver and hence I 'HAVE\ to field the calls coming through which was not going to voicemail. Clearly MTN can afford losing business better than I can! If someone interested @ MTN comes across this post