I have a wireless cyclocomputer that has been working great for years. When I came back home from a 1 week vacation all the data was gone on the cyclocompter. I even had to reset the tire size. Now when I ride everything works great unless my speed is under 10 mph or over 20 mph. When I climb or descend the display goes to "0" and it won't register my speed, distance or time. Any ideas?