The brake get stuck and consequently the wheels are not moving. Help!!!
I am sorry you have problems with your buggy. The first thing I can do for you is to recommend our stroller cleaning and maintenance guide as I think you should try lubricating the wheels and brake - maybe they are not loose and oiled enough.
If that doesn't help, and you're sure all is put (clicked on) right, you should definitely write to the seller you bought your stroller at, as this sounds like a problem that should be covered by a warranty. If the warranty protection is not applicable, they should at least recommend spare parts or a service that should help you make your pushchair functional again.
In any case, go check if the wheels are not locked, lubricate all the joints with silicone oil or something like WD-40, and if that doesn't help, ask the seller (or the manufacturer, Moweo, if that is possible (look for contacts in the manual) directly.