Kitchen seller wants the remaining payment in cash, does not want a transfer

In the event that insolvency proceedings are underway, the insolvency administrator will be able to insist on a renewed payment. Rightfully so! Then you would have to pay your 10,000 twice... so make sure you find the Handelsregister-B (should be on the business paper of the contract) and if necessary ask the local court

In the event that the insolvency proceedings are underway and the kitchen installer still acts as if nothing has happened, it is rather likely that the kitchen installer would be committing an offense.

Of course he is committing an offense but the money is gone anyway.

If that is pending, it is best to check again on the day of the final kitchen assembly / cash payment whether insolvency proceedings are ongoing. In that case, I would then not pay the installer with reference to the insolvency proceedings.

In case the insolvency proceedings are ongoing and the kitchen installer still acts as if nothing has happened, it is more likely that the kitchen installer would be committing an offense.

yes, but the OP is probably more concerned with that as a secondary matter. The insolvency administrator (again: if present) will demand the money a second time.

Exactly like that. yes, but that is of secondary interest to the OP. The insolvency administrator (again: if one exists) will demand the money a second time.

You should be able to protect yourself from that. If the OP behaves according to the contract, even checks whether there is a current procedure, it becomes rather questionable to have to pay a second time? Insolvency law is not directed against the customer, is it?

The thing is that as a debtor of the company, upon becoming aware (this includes knowing that the company is currently in suspension), you have to pay your outstanding debts to the insolvency administrator. Because only the insolvency administrator can ensure that the creditors of the company are paid equally. The insolvency administrator is the only disbursement and payment point in the procedure!

And if after months he realizes that Tumaa still owes 10 TE, he will get it. The former managing director is no longer authorized to receive the money. But if the money is already gone from the managing director, then Tumaa just ends up empty-handed and pays twice; the insolvency administrator doesn't care, he simply obtains a judgment against Tumaa and that's that. How Tumaa then recovers the money from the former managing director is none of his business.