Hi, I'm not sure I'm in the right place but hopefully someone can set me on the right track.

I have standby hours that I am paid for and have been doing those hours with minor deviations for many years. This has basically formed part of my income in a reliable way. The company is trying to reduce the hours that I work standby and is therefore reducing the money that I earn and I do rely on this income. Is that ethical or more specifically, can I do anything about it?

As an added note we have just been bought by a new company and their standby already pays less and now they are trying to reduce my hours.