Incorrect credit ratings on system

I've had a cell phone contract for over 2 years with Vodacom. Last week I wanted to upgrade my contract and all of a sudden I've been downgraded to an extremely low credit score on Vodacom's system. Apparently now I can't even afford the cell phone and contract package that I've been paying for more than 2 years. The personnel at two different Vodacom outlets logged a query to rectify this. I checked my own credit score and I scored very high. Now, I've been waiting 2 days for any feed back regarding this. I've been a loyal customer for years, this is very disappointing.