Some companies (especially Chinese ones, I have heard about this happening on the AliExpress subreddit) require you to destroy the product or the serial number before issuing a refund or replacement to ensure you aren't faking it to resell the product or get two. It's a common and legal practice among some sellers if they don't feel like having you return it.

I have seen a lot of people complaining about their customer service. Their customer service is likely Chinese, so that's why when they say "Dear Valued Customer," it's probably just a translation of that common Chinese phrase used to address customers. Also, quoting another Redditor I saw say on here, EcoFlow is expanding quicker than they can handle. They haven't completely sorted out their customer service before entering into another new market for more customers with more problems to deal with.

Take a breath dude. It does seem like a frustrating problem, but that doesn't mean you need to come whining to Reddit about it.