Kola Opavel

Hello, about a year ago I bought a bike in Opavel along with other accessories for it. I was satisfied with the bike until I put it on the guarantee "service". After the service, I picked up the bike and found out 2 other defects that were not on the bike and also that the bike was not actually adjusted. Lap I drove them back, vendors took it reluctantly, I am surprised that I did not get scolded, the next takeover were fixed two glitches that have not been on a bike, but still nothing derailleur. A year has passed and it is time to service (the bike traveled about 700? - not even that), I decided to round place to another service where I had just CZK 340 per change cables from the rear derailleur (stainless steel) and the actual adjustment as switches , so derailleur. Satisfaction highest. After taking home, something began to crack, it was a pedal. The tread was repaired and I drove another 100Km - IT'S FINISH CENTER. How is it possible? Do they give poor parts in Opavel or do they damage the wheels themselves? Wednesdays have to last several thousand Km and not even ONE. I am really not satisfied with the bike and I would not buy a bike with you again. Another finding: When I was buying a bike, I had over 20 thousand in my pocket, the salesman was great when I sent to buy a family member's bike, he cursed like a bricklayer. He bought a bicycle for a little girl (4000Kč). The salesman was reluctant to say he had never seen it before. So please tell me where is the problem ????