How Many Syringes of Radiesse Are Needed for Hand Rejuvenation?

I was informed by my clinic that the price for hand rejuvenation using Radiesse filler was £500. I had the treatment and at first my hands were swollen. The swelling then went down and they are now the same as they were pre-treatment. I have looked at photos pre-treatment which confirms this. My clinic now says they only used 1 vial and that 2 vials are normally used and I would have to pay another £500. Is this normal?