well it seems your English is good enough!!
have you tried without the gate patched to strum, a change in note should trigger rings
the transpose function is on the keyboard - so it is just general playing etc and not the frequency cv input
it certainly does not seem to be correct
I suspect you might be right about the quality of the build - was the vendor a known builder - ie have they built and sold a lot of these or was it just some bloke and a soldering iron?
I would initially try to contact the person you bought it off, describe the problem and see if they will fix it or refund - if you bought it with that possibility
if this doesn't work out then you might try the muffwiggler music tech diy subforum - there is a sticky list of reliable builders there - and of people looking for them - and there's also a mega - unsuccessful mutable diy builds thread - you may be able to find better help there!
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities