Frustration with Time Capsule

I ordered Time Capsule as soon as I read about it. Thought it would be just the ticket. I set it up when it came and it worked - until the next day. It forgot it was supposed to back up my computer and the only way I could get it to do it was to choose "change disk", then select the time capsule and reset all the options. Today it can't even find it, even though it is on and glowing green. It is making me crazy. I am online through a neighbor's network.