Is it permissible for a partner to demand that his associate withdraw from the company due to his continuous breach of financial obligations, and should he be repaid what he paid (40,0 Euros) or should he be repaid his share of the company in its current state (with its payments and debts)?

This partnership is not valid except for the amount of money actually paid, because one of the conditions for the validity of a financial partnership is that the company's capital must be in cash (an asset), not a debt, and that it must be present at the time of the contract. Each partner has a share in the company proportionate to what they paid of its capital at the time of the contract, and they are entitled to profit and bear loss proportionate to their share.