I just wanted to give you guys an update.
I finally decided to send the lens straight to Canon repair center. I did send it last week and today I had the answer form Canon the repair costs. Total amount is us$283.00, including the shipping cost for us$14.00, so I think is a pretty decent amount of money.
I had already paid the repair cost, so I'll be waiting for the lens to come like it should.
I'll update again to let you guys know if everything it's ok with it. Maybe I'll post some samples.