Upgrade Debit Review Down Grade!!!

Vodacom informed me that my vodacom credit score had been reduced from a 7 to 4 due to the fact I am under debit review. I am currently paying R 1191.73 pm for my contract which ends in January 2022. I tried to upgrade my contract and the only upgrade contract/phone that I now qualify for is A Tecno Spark 7 phone value around R 2000.00 . If I do not upgrade my present contract will revert to a month to month contract, at a cost to me of R 1191.73 pm If I take the offered upgrade Tecno Spark 7 phone with 100 min and 1G data on a 24 month contract cost to me R 250 pm. I now find myself is a possession as I definitely don't want a Tecno Spark 7 upgrade. I would like to reduce my monthly contract payment from R 1191.73 to around R 600.00 pm. I an unable to even discuss this matter with the upgrade department as the system will only allow me to upgrade to a Tecno Spark 7 and nothing else. I dont want the upgrade offered and I cant reduce the current contract amount even when the contract is month to month. So now Vodacom what am I expected to do.?????? please explain to me in detail ?? the logic behind this situation .How and why debit review is now an issue. Be transparent honest and open and treat your customers fairly.