Dissatisfied client

I am disappointed the way Telkom handled my upgrade. I'm due for upgrade and went to the store for upgrade & the store didn't have the phone I wanted. Few days down the line the agent called & told me my upgrade is declined. Why upgrade is treated like an application for an additional phone? It was an upgrade for heaven sake. I've been a contract client for years without skipping payment. Can someone from from Telkom make it sense to me why upgrade is treated like a new application of an additional phone.