Not sure what SP you applied with, but with VSP, the reasons why the credit vetting system might decline you:
1. MONTHLY INCOME TOO LOW
2. LISTED ON ITC
3. NO CREDIT HISTORY
In most cases, if the client is listed on ITC, the application will be declined outright and ITC needs to be contacted. But when it comes to someone who mabye earns less than the preferred amount, VSP most likely will still approve the contract, but limit you to a certain portfolio of packages that you are allowed. For example, some one who does not meet the desired criteria, but have a clear credit history might be limited to the Top Up packages and will not be able to take out a Talk 500 for example. The store where you applied will be able to tell you what packages you qualify for once the credit vetting have been done on the system.
In some cases, if a contract is declined, the store can request a declined review from VSP New Business department. In such a case, all docs (application, ID, bankstatements etc) will be faxed to them, they will review it and then either approve it or decline it.