how come loan repayments say one thing online and when you ring for decision it suddenly changes

[longwaytogo]

Trying to buy a car and looking online for a loan but everytime we apply the interest rate suddenly rockets from 5.8 to about 7.9%

Finance at the garage was actually the lowest interst rate that we have been quoted but people say not to go with finance and that loans are better but at this rate the car will be gone.

now i'm really confused having just got info from garage out the interest rate quoted is flat rate of 5.25 which would be about 10.5 apr so that is the highest interest rate but the lowest repayments over the same length of time.