Valid & Invalid transactions

Q: Is it permissible to pay somebody for bringing in business? I work in sales and people (3rd party) bring me business. If I make a sale they ask me to give them money which is already decided it doesn't matter how much money I make on this sale, they want what ever is decided before. Now the question is if I pay somebody to bring me business then what about other guys who work with me in sales? Because if the (3rd party) doesn't bring it to me it will probably go to my coworkers please tell me what Islam says about it?

Q: The other day, I ordered a pizza online, and paid with my mother's visa debit card. My mother allowed me to use it. I didn't have enough money in my own visa debt card to pay for it online, so I asked her for hers, but gave her the money back in cash on the same day. The day after I was on the pizza company's website, and I learnt that when one orders online, they have to have the owner of the payment card present when the pizza is delivered. They then must show their own payment card as proof as the below term states (taken from their website): "The owner of the card used for payment must present this card on receiving the order. Card payments are secure". I didn't know I had to do this until it was too late, and the transaction was complete. When the pizza arrived, all the delivery driver said was "you ordered online" for which I replied, "yes".  I thanked him, and that was that.  He didn't ask me for proof of payment. So I paid for the pizza, and it came to the right address, and I confirmed that I ordered online when I was asked by the driver. The only thing I didn't know, was that one must show payment card upon delivery of the item. Our beloved Prophet (Sallallahu Alayhi Wasallam) taught us to honour conditions, so that is why I am concerned here. In this situation, what is required of me? Was this transaction still valid?

Q: A approached B to finance the purchase of a house which he did not see for 1.25 million rands and A agreed to buy the house from him at a higher price. He also borrowed 150 000 for transfer costs and renovations and this amount was included in the repayment of the house. The repayment price was worked out according to bank interest rates of 12% per annum with a total amount agreed upon. It was also agreed that should the payment be made before the 7 year agreed period then the total repayment will be less than the agreed amount, it will work out pro rata.

1.What is the shar'i status of this transaction.

2.What should be done to correct it.

3. Payment have already been received for 1 and half years, how should that be rectified.

Q: I intend to purchase a car that has a warranty. The dealer offered to extend the warranty by 5 years for an additional amount of R3000. The warranty covers towing and fixing if the car breaks down and replacement of parts. I notice that the policy is with an insurance company. Is this acceptable?

Q: I am purchasing a cellphone and have been offered the following option for extending the warranty:

Pay $10 a month and if you lose or break your phone, you can get a new one. Plus, every six months, you can trade in your old phone, pay the difference and get a new one.

Q: I want to buy a car. If I buy it for cash then the price is R260 000, and if I buy it in instalments, then I have to pay R300 000 i.e. R40 000 extra. Is it permissible to buy on instalments?

Q: I work as a middleman, taking orders for medical equipment, surgical instruments, etc. I make money through charging a commission on the orders. Is this permissible?

Q: Can you do a business transaction with your spouse? E.g. the husband wants to buy a car. Can the wife pay for it and sell it to her husband with a profit on the sale of the car?

Q: I run a supermarket. Is there any limit on the amount of profit that I can make on the items that I sell?

Q: My mother bought a property with a share from her brother the price of the property has doubled and now I want to sell the property. Should I give him the same amount of money he invested at the time or do I give him profit because the price of the house has doubled?