Tethering iPhone 4 Vodafone Romania

Hi,
I bought my iPhone 4 from Belgium last summer. I am a Vodafone Romania customer. Working on the road, I used the tethering function a lot for connecting my MacBook to the internet. This, until December 2010 when Vodafone launched the iPhone 4 in Romania. I got a carrier update and my tethering option disappear. After a few unsuccessful calls with their support team they told me that they removed the option and I should contact Apple or jailbreak my phone.
I’m completely against jailbreak and that is why I bought an unlocked iPhone from Belgium.
My problem is that I had the tethering option before and they removed it without informing me. I should have been informed about the update and what it contains. The update wasn’t mandatory and I could have postponed it.
This is not fair. Tethering was an advantage for me when using my iPhone and now I have to decide between changing Vodafone or jailbreaking my iPhone 4.
Please advise me.
Best regards,
An Apple big fan and customer,
Mihai.
iPhone 4 iOS 4