What is the ruling on being compensated by an insurance company with an amount based on invoices that have not been fully paid? And what is the ruling on being compensated with an amount less than the value of the invoices but more than what was actually paid? And is it permissible, if the excess amount must be returned to the insurance company, to give it away as charity if returning it is impossible?

Permissible insurance is only cooperative (takaful) insurance. Commercial insurance is forbidden due to the elements of ignorance (jahalah) and ambiguity (gharar) it contains. If the insurance your workplace subscribes to is a legitimate cooperative one, then there is no harm in benefiting from what it provides, provided you adhere to its conditions and do not forge fictitious invoices. Any amount exceeding what you paid must be returned to the company or given as charity for public welfare. However, if the insurance is a forbidden commercial one, the insured is not permitted to benefit from it by more than what they paid. Any excess is considered unlawful wealth that must be disposed of by spending it on Muslim welfare or for the poor and needy. In summary: If the amount you received from insurance is equal to or less than the subscription amount, there is no harm. If it exceeds that, then dispose of the excess by distributing it for the welfare of Muslims or to the poor.