ᐅ Architect → Coordination? What does that mean?

Hello everyone,

I hope you can give me some advice or tips.
We bought a house in shell condition and decided to have an architect handle the interior fit-out.
We have a budget X for the interior work, but there is no detailed breakdown of what may/can/should cost what.
We constantly have to chase the architect to get a price range for each item. For example, when buying tiles, he sends us to the hardware store but doesn’t tell us how much per square meter (square foot) they are allowed to cost. So, again, we have to call him back.
He orders a front door and sends us a photo. The door was white on both sides with frosted glass, but the one delivered was white on the inside and wood-like on the outside with clear window glass! We never wanted clear glass, and he knew that! More back and forth calls, and now we have to buy a film for the glass because the company doesn’t sell front doors with frosted glass. Great! That’s how the communication works.

Regarding the kitchen tile backsplash, we clearly explained multiple times how we want it. A few days later, the backsplash was done—but the way the architect wanted it, not as we agreed. So again, a phone call, and ultimately some tiles had to be removed and redone.
It’s getting frustrating!

And now we have the next problem:

The architect chose a sink, shower screen, wall-mounted toilet with seat, and other sanitary fixtures from a very expensive bathroom supplier. We didn’t know this. The bathtub is already installed—we didn’t see it beforehand, so once again, we weren’t consulted. When we looked at the sanitary fittings, it was an absolute no-go! Completely unsuitable in terms of style...
and price-wise, the cheapest of the cheap! If we were to pick what we want, of course, we wouldn’t reach the price in his current offer. We actually like sanitary fittings at hardware stores that are also much cheaper. He insists we must buy from this bathroom supplier and probably even the items he selected...

What can we do? What options do we even have? If that bathroom goes in with what he chose, I won’t move in... *sigh*

Unfortunately, we only have a work contract with him, and I fear we have to comply... I hope someone here can help!

One more question:
Do we have the right to request invoices for the services provided (tiler, tile purchase, etc.)? To ultimately check whether he actually used the full amount allocated for the interior fit-out? It could be that he buys everything cheaply and keeps the rest for himself...

Thank you and best regards