Vodafone India — 2G net pack activation on a recharge of 3G data pack

I recharged with a 3G data pack. The 3 G data was on for some days, then the data switched to 2G. I called the complaints contact (198) and got replies saying my phone itself did not support 3G and such. I tried explaining but the so called experts did not understand. I have been charged extra for using 2G data and they still have not called back, which they promised they will.