OP, I think you provide an interesting point about customer service and owning a business. However, this for better or worse, is an illegal business.
At one point or another, it's a privilege to be able to buy high end replica watches from overseas from an unknown source and pretty much be certain you'll receive the product. Fact of the matter is, there are far more customers than actual TDs you can go to get get the watches/services.
That being said, I've never had a "perfect" replica, they've all had issues, from cosmestics to mechanical. It's often easier to handle it on ones own than deal with overseas interactions. In particular, replacement parts do not have the same fulfillment as completed watches. Regardless how big or how small the part is, the vendor needs to contact their supplier, who may not even necessarily be producing the watch and simply just stocking the watch. And if they manage to procure your replacement part, it may not be until the next batch of watches are being assembled. I've waited 7 months on a replacement dial, but I eventually got it.
Up to a point you've noted that you had issues with other replicas, so you should pretty much know that it comes with the territory. Atleast you don't have a local watchsmith that promises deadlines and fails to deliver. I think that is a bigger problem than an illegal overseas supplier as fixing watches is an actual legit business.
The resellers of these illegal products are just that, resellers. And even if the vendor is an actual manufacturer, well again, the demand of the product exceeds the access that customers have. I think it definitely sucks paying for a product and having to wait an extended period of time to actually enjoy. But on the other hand, do you really want to pay like 10x++ for a gen counterpart? With a gen, you're paying for the service. With replicas, you're basically playing roulette for a large savings...
All TDs have their quirks, I definitely feel your frustrations going with a bigger TD you just expect better service. But again, far less TDs than actual customers. You can't buy high end replicas just from anywhere/anybody. And I certainly believe you're aware of this and continue to buy replicas even with your past issues...