State Bank Of India [SBI] — car loan interest rate has been increased from 8.9% to 9.8%

I have taken a car loan at 8.9% floating but recently the car loan interest is increased to 9.8%.
I have called the branch several times but they didn't replied and told to call me to later but they didn't replied many times i called, even they told me that they will check and update but still i didin't get any update, later i called customer care to get update but i got an email id to check with branch, i have wrote a 2 mails to the branch but i didn't get even mail reply from branch till date.