The water is running into the drain line continuously what should I do?

Running from what? Hot water heater? Washer?

Running from the rainsoft water tank into the drain line (sewer line)

It is running from the rain soft system I am a handy man and take care of 17 rental properties and I Iknow what I am talking about.but what I don't know about is the rainsoft system, it is running continuasly into the sewer line the water bill this month was almost
700$ they will adjust the bill but it has to be fixed first,

I don't know of any water dpartment that will adjust a bill just because a person has a faulty appliance. In your case the regeneration cycle motor is stuck, unplug the unit and the valve should close. If this does not close in the first minute then try to manually rotate the face of the timer if its an analogue timer. If its digital leave it unplugged for a minute and then plug it back in and reboot.

You need to be much more specific in describing your problem. We cannot guess at these things and help you. What are you talking about? I cannot see your appliance. DrTom4444