Contract declined after being approved

I app**** for the iPhone 11 Pro Max 256GB phone. I received a call from the consultant who was extremely helpful. I did the security question, and she told me I was successful approved for the contract, they even sent me a pre approval sms, and said once I was debited, they would send another sms to say when the phone would be delivered. As soon as I got off the call with the consultant, I received an sms saying my application was declined during credit vetting. I have 0 debt on my name, I tried calling but no answer and I received no explanation as to way it was declined. What nonsense is this?