If you're supposed to meet someone at a restaurant on a particular night, and several days in advance you email, text, and/or leave voice mail saying you can't make it, would you expect the person to acknowledge they got the message? If you heard nothing back would you be worried about them sitting there waiting for you, or would you just shrug it off and tell yourself you did what you could?
I would just let it go. If they can't return a call or anything. Than, they are not worth my time.