DSTV renaging on payment terms

DSTV sent out an email last month advising of price increases and ways to skip the increase, To pay a year in advance the wording reads "Pay a full year's subscription in one payment before 31st March 2018 to take advantage of current prices and get your 12th month on us" This I tried to do but was initially informed that could not be done as my billing date is 10th April and I could get a free month AT THE NEW PRICE! Eventually, after I argued this, the operator then said she would contact me later in the month invoicing me at the old rate but I would lose several day's subs. Not being happy with this I again called today and was informed that I was now on monthly billing! News to me! I again repeated that I wanted to pay a year in advance at the old rate - not possible - escalated to supervisor who could not hear me on a landline - put phone down after over 30 minutes on this call. Tried again with Cape Town number, got a much more alert operator called Sheridan who made a plan, pay the full year's subs into their bank account and then phone again to sort it out. Can't pay on their website as their system only allows you to pay the amount they claim is outstanding...one month! Total time on the phone on 14th and 21st March, around 70 minutes. Staff understanding, either limited or obstructive, customer satisfaction -zero. I still have to resolve this issue, having made the payment, but cannot understand how such a large company can show such a high degree of incompetence in advertising a deal and then NOT honouring it. Anybody else had a similar experience?