Vodacom - "YOU DONT QUALIFY FOR THIS PACKAGE" with no explanation

I have been a paying customer for a couple years paying over R1000 per month without ever missing a payment. I am soon due for an upgrade of which I would not like to ipgrade my device and I would instead like to alter my package in terms of data and minutes. I called the Vodacom upgrades department to discuss this after receiving an SMS stating I should do so to paying full price for my current package on a month-to-month basis as any specials agreed to at the beginning of the contract would lapse after the contract period. I asked for a price for my desired package and they gave that to me. I also had a look online and found my ideal SIM only package for R200 cheaper than the quoted price. I requested the upgrade option online and it said I dont "qualify" for this package. When I spoke to the same consultant over the phone again regarding this he stated " Sorry Sir you do not qualify for this package" but he could not explain why. It is quite clear that Vodacom are trying to squeeze me for an extra R200 per month even during these tough times which is extremely disappointing. I would really like to understand what would make me "qualify" for this package. I liken this treatment to trying to buy a product from a supermarket to be told by the manager that I cant buy that product as I dont qualify for it. I must please buy the full price version. I will give Vodacom the chance to resolve this before I cancel my contract and move to a different service provider!