Hi Juancho
First of all Tank Sports does not sell to VIVA, that I know of. Tank Sports does not allow drop shipping unless the dealer is reputable. I would also contact Mike Turber at Tank Sports and let him know about this as this is Copyright Infringement & Fraud in the worst way, the biggest thing is Fraud. Mike Turber at Tank
mike@tank-sports.com . Send him the web link and let him know your story. I know he won't be able to help you with the bike but he can do something about the VIVA having Tank's bikes on their website.
Like I said earlier did you use a Credit Card to purchase the bike? if you did do a Charge Back through the Credit Card Company. They will help you with this as I had to do it some years ago against SunL. Yes SunL stuff 95% of it is junk as far as I'm concerned.
Please don't rip on all Chinese ATV's & Motorcycles. I can't diagnose the problem you are having unless I talk to you...but I know what I sell is Chinese. I have been selling American Lifan, United Motors, SikkMX, Redcat, for over two years with little or no problems at all.
Honda's, Suzuki's Kawasaki's & Yamaha's bikes are built in China, Korea, Taiwan etc. etc. Look at their websites and see how many are made in different countries. Here is some proof.
http://www.linhaigroup.com/english/contact.asp
http://www.yamaha-motor.co.jp/global/link/index.html
http://www.globalsuzuki.com/globalnews/index.html
http://www.yamaha-motor.co.jp/global.../01/joint.html
There are many others if you do some searching.