On Call - Do You Get Paid?

So the company I work for decided to withdraw funding for on call support last week. This evening I receive a text out of hours, asking me to get in touch to fix a network issue on site. So they've stopped funding for on call support, and now they are asking me to support a network emergency in my own time (i.e. Be permanently available to support the network)... I just don't get it. Has anyone else had a similar experience, and if so do you end up just doing the on call work anyway, or refuse to do it? I honestly don't know what to do because I want to help and be a good engineer, but I also refuse to be taken advantage of & be in a situation where I constantly have to hope there isn't an out of hours problem I have to attend.