I would like to ask you about the permisibility of mobile phone chash-back contracts. I am not sure if you are aware abouth such schemes, but it works as follows:

i) The company or high street shop offers a contract over one year (or some other period) in which it provides a customer with a handset plus a fixed quantity of calls or air-time for a price (say 30 sterling) paid in monthly instalments. This amount is to be deducted directly from the customer's account via direct debit.

ii) The company or high street shop will after a period of time return to the customer a lump sum equivalent in amount to what the customer has paid minus a small amount. This small amount therefore seems to be what was paid in exchange for the product or service. (Sometimes this amount is as little as ?£1 multiplied by the duration of the contract in months). The returned lump sum might be given as a single payment or in instalments distributed throughout the duration of the contract. Also, sometimes it might be conditional to the submittal of the invoice statements to the high street shop by the customer. In some cases two parties are involved; the customer and the company. However, many other times, there are three parties involved in the transaction: the customer, the broker/agent (which is usually the high-street shop), and the service provider (which is usually a large company such as Orange or T-Mobile in the example of mobile phones contracts). The customer is paying the money to the large company while getting cash-back from the broker and the service emanates from the large company.

These cheap contracts attract many people to take them not merely for their basic needs but also as a luxury or for future trading and business since they are able to acquire expensive products cheaply which can be re-sold again at a profit.

Is this scheme Islamically permissible?