Hair and make up, charging extra for new date

View quoted message So our original wedding date was June 2020 and had to postpone to this year. However, since things are still closed we need to postpone for a third time. We have a contract, does not mention anything about a price increase or covid etc. They didn’t charge the first postponement but are now. Don’t feel it is fair given that we cannot control the circumstances and 400.00 is a lot.

We had to postpone our original July 2020 date to this June. My hair/MUA is honoring the original agreed upon price. I'm not sure if that's her choice, or if it's because I had signed a contract though.
Had you signed a contract with the previous price? Does it say anything about price increases in any circumstances?