Bad customer service

Im not happy with your service from mtn rosebank, the lady who was assisting me, from last week she's telling me the promotion is not on system and she has emailed their head office in India for the promotion to be on system and when i called mtn head office and i was told she **** about the promo not on system and the India head office, when i called to find out why she's not telling me truth, she started shouting at me.