Mirraco Project 18 - your opinions?

I have a Harro Mirra 540 18" and its is a complete shitter. I have had it less than a year and it has caused me endless problems. I ride it for 30 minutes and The back tire creeps forward and loosens the chain, and with caused the peddle to go into a different slot on the chain holder. Just everything on it gets loose, and when that happens the peddle takes long to catch on, Like i will press down on peddle to start going and it will swing all the way down then catch and start working. I am taking it to the shop this week i can not take it any longer. I have fixed it over 30 times. I wouldn't recommend it.