1) The remote is not communicating with any of the functions on the receiver. The volume is not working. When I press any button on the Use Mode red light comes on. 2) Also when it is functioning, the off/on button doesn't work. It does sometimes only if I press it very hard

I can give you several tips to try and see if we can get it going. First make sure you have the correct devise selected with the remote. For example if you are using it for the tv, make sure you have pushed the tv button on the remote first, and so on for all the other functions for your reciever. If this is not the problem try changing the batteries and make sure they are in correctly. Weak batteries will allow the red light to light up on the remote but it doesn't have the power to send the signal to the reciever. the other option is that the remote is simply wearing out, or has some type of dirt insde it not allowing the buttons to make contact with the metal strips inside the remote. You can sometimes find a store like Radio Shack that will be able to check and see if the remote is acdtually sending a signal, try calling around and see if someone has one of these detectors. If none of these help, try getting one of the universal remotes from a department store, they work with just about any brand of electronics and are much cheaper that a new remote. Here are a few links to sites that carry almost all brands of remotes in case you need a new one.
I hope this helped.
MrRemoteControls.com
Remotes.com