So, I read the whole post and 100% Plush Wonderland seemed very unorganized and unprofessional. And I do not believe you have been speaking to the same person this entire time as the email where they confused you as the customer would have not happened. I used to work in a call center where we would also work on emails and these types of companies tend to seek outside international services as it is cheaper labor (I'm mexican but my call center was working for an american company). And emails were typically handed to those with lower english skills. I believe that may have been the case here and they only forwarded the message to someone more capable for the situation after they saw how badly it turned.
Another thing I noticed as well is how little they helped you, not only in not telling you that the plushie's cost of production would rise from your changes, thus making the plushie cost more (They needed to 100% disclose that to you) BUT ALSO in the lack of promotion. That is ODD and just a bad business move. Other companies when they collaborate with eachother, BOTH SIDES market the campaign. One of the biggest examples is Miniso x Sanrio. One of the reasons why it's such a succesful compaign is because both Miniso & Sanrio heavily promote their collaboration as this increase sales and makes for a succesful compaign. So Plush Wonderland not doing this tells me one of two things, either 1) They did not care for the collab anymore/ had low hopes for it or 2) A very bad comprehension of collaboration works and marketing along with poor organization.
So for the first point I noticed that you mentioned how they posted an instagram post promoting the plushie but how it got buried under their newer posts. It kinda seemed like they made the post JUST to make it but didn't really care for it. And for the second point, I do not understand how they even thought running two compaigns simultaneously was a good business plan in the first place? If you have 40 customers, 20 buy from one compaign that needs 40 sales and then the other 20 buy from the other compaigns that just needs 30 sales, obviously that would make both compaigns fail and as a company YOU DON'T WANT THAT. The better plan was to let the first compaign end, refund the money and of course the people would still buy the compaign that is cheaper and bringing 20 more people to a compaign that already has 20 buyers and only needs 30 sales; that would make the compaign a success by even exceeding 10 more sales. I FULLY AGREE WITH YOU that this seemed like you were talking to a small one person business instead of a company that has had several other sucessful compaigns with other collaboraters.
It is a shame that you had to go through this awful mind boggling experience ;; Truly dissapointed in Plush Wonderland and I hope in the future you can get a better deal than what they gave you <3 LOVE YOUR WORKS, KEEP GOING PRI <33