It is strange situation - ordinary you can find rebuilt kits (jets, needles, gaskets, membranes, O-rings, circlips, springs ...) for most carbs on C-motos, but I can not find one for MV30P. There is a guy from China, "Humanbeing" - if he sees this thread, he'll probably give you some "Taobao" link with that kit.

Or, you could try to call people from "SSR Motorsport" from California. Their XF 250 (aka. "Qingqi") is fitted with the same carb. Maybe they have some spare parts.

And yes, you can fit different carb. I think that cheaper carb would be plain, slide type PZ30, but you would be forced to modify/make intake manifold because MV30P have so called spigot type connection, and PZ30 are commonly with... Damn, I forgot English word for that type of connection!