Indeed, miniaturicum.de are notorious for lack of communication. You order, pay and hope for the best because they will not respond to queries.
This has not been my experience of dealing with them at all. I've placed two orders in the last 6 months with good communication.
In my first order one of the blisters was missing a figure, which was sorted with a little delay, as I feel it's a bit of a one man show and he had Covid, but the communication was there.
On my last order I'd forgotten to include a blister, which I communicated to them and they happily added it to my order after they'd sent me a paypal request.
Here in Spain, I normally get all my stuff through Goblintrader and they've always been great, but not even they will allow me add things to an order once it's gone through.
So thumbs up for Miniaturicum from me