Credit vetting false

So, I app**** to Telkom online for a laptop contract. They got back to me and we finalised the sale, then next thing I knew I got an SMS saying "order has been declined during credit vetting". As i was confused because i know i have a great credit record, and a stable job, I confirmed my status with the Transunion. I don't know if Telkom simply doesn't want customers or perhaps there was an error on their side. I already have a contract with them for the past 11 months, so I don't understand what went wrong.