In a (rare) defense of vendor companies, the sales assistants seem to me to be actual separate people (obviously using fake Western names, which is fine I think). Accordingly, different buyers prefer different ones, for reasons of promptness, clarity, follow-through, updates, flexibility, perceived honesty.
The absence of form-of-payment statements (especially surcharges) and shipping fees is indeed annoying, but I can only .assume that it's a dynamic environment (trying not to get booted from processors, possibly with funds frozen) and varies by buyer's market nation. Many online "real" sellers of other products will only show s&h halfway through checkout, which is frustrating when you're hooked on [political remark withheld] Amazon Prime.