Long standing customer discriminated for being under debt review

I am shocked. We ordered an iPhone 13 on the 12th of December and was told we would have to wait until January for the device, well now its March. Phoned a retentions agent and was told the order was cancelled because there is no stock?! okay, so he says we need to reorder, he tells me there is no stock on the 13 and limited on the 13 pro. we tried to upgrade to a 13 pro and were met with a "new policy" that prevents debt review customers from upgrading? first of all, this contract falls under monthly expenses by her debt councilor, we have been paying the account since 2005, we had no issue paying for an Iphone 11 on a 24 month contract before! so explain to me how, My mother who has been with Cell C since 2005 is not allowed to upgrade under debt review and how the Iphone 13 ordered on the 12 of December was processed??? explain this too me , please, if this is how you treat long standing customers, might as well get my mother to cancel the contract.