Rock&Rocker Upgraded Automatic Pool Cleaner

I watched this youtube clip that made me pull the trigger: (search for ROCK&ROCKER Robotic Automatic Pool Cleaner Review - HJ3052)The first purchase was not impressive: Amazon sent me a used one. One can tell it by (a) the box was repackaged; (b) the body had some scratches; (c) the filters contained debris. I made an immediate replacement request and Amazon sent me a brand new one (thanks Amazon).The first week was excellent with the new one! It cleaned the pool and the wall tirelessly just like what you see in the youtube, and we all liked it.The second week I saw the cleaner was turning around again and again, then it was found that one of the tracks was off the wheel as shown in the picture. I like the machine so much that I did not want to return it, and i thought it could be a loose track, so I called Amazon to check if they could give me a new track. Amazon associated helped me (thanks again Amazon) to find the manufecturer's phone number, which is a nightmare: no one picked phone no matter WHEN you call. So I left my phone number and email, 3 times, expecting them to contact with me. Absolutely nothing happened. Guessing the off wheel track could be an accident, so I managed to fix it and put it back into the pool. Within 2 weeks, the track was off the wheel 2 times. Enough is enough! I have to see goodbye the the little one and just returned it today.Here are something I like:(1) Price is fair (under $600);(2) It cleans the wall pretty well;(3) It is simple, no wifi, no programming (really that's all you need)Here is something they can improve:(1) CUSTOMER SERVICE!!! If you don't care customers, do you think customers will care YOU?(2) They should list their parts in their website to allow us to buy when something unexpected happens - They don't have the list;(3) The power line is easily got tangled, not tangle free.