The ERR70 means there is some kind of communication problem. If doing the things Canon recommends doesn't help then it may need repair. There isn't a place that does repairs on digital cameras in Kansas City. The closest is Phototronic in Topeka. Otherwise it would be sending it in directly to Canon.
They don't do repairs there unfortunately. I've had a tough time finding camera repair in KC. They are great at answering questions and might know someone who can help.
Thanks! Your answer is awaiting moderation.