Incompatible with my Twingo and not solid

I have a Twingo 1, 1997.
This product is not compatible: Can not connect the rod of the lock mechanism to bought barrel.
It was necessary that I tinker to lengthen the rod of my Twingo so she can reach the attachment of the barrel. But by tweaking the mechanism, a barrel of finished plastic parts to break. There I had to re-hack to replace the broken part (small angle). You tell me, for that price you could not expect the top quality.
The result: it still works, but for how long? (Most parts of the mechanism are plastic ...)
Only positive: the price. At a Renault dealership, this room is 110 euros ...