Who should pay Zakah when partners

Q: We pay the Zakah (obligatory charity) due on our company, ourselves, to those deserving it whenever a Hijri year passes in proportion with the invested amount and the percentages of partners which changes from one year to another. This year, we had to indulge in some governmental transactions entailing that a Zakah paying certificate be issued from the Department of Zakah and Income. Going to the department, they demanded the Zakah of the past three years, the actual duration of our company, be paid in order that the required certificate be issued. We have already paid it to them intending it to be the Zakah of the forthcoming year. Is this permissible? I mean: may we deduct it from the Zakah of the forthcoming year bearing in mind that it is a reasonable sum of money and that some partners have changed?We agreed with a merchant in Bahrain eight years ago to invest a given sum of money on the condition that he shares with us at least 10% of the sum. The duration of the agreement is one year that may be extended based on the desire of both parties. We deputized him to invest the capital in the field he deems suitable in Bahrain, such as purchasing lands and stocks. However, after the passage of one year, we did not extend the agreement mentioned above and demanded the man to pay off the money but he did not (Part No. 9; Page No. 359) pay the sum of money we had given him claiming that the land he purchased did not equal a quarter of the original value. He finally agreed to pay the money two weeks ago, after seven years of demand. The deal was that he would not involve us in the last transactions loss and will pay off the sum of money we had paid him through deferred checks whose date of maturity is not due yet. The question is: what Zakah is due on us for the latter transaction? Is Zakah due on the invested sum of money for the past eight years? Or, is Zakah due on the one-year duration of the agreement? Are we to pay Zakah immediately or wait until we receive our sum of money in full from this man? We hope for a reply with thanks!