Is it permissible to agree to a deferred sale with a new contract if the buyer is unable to pay the agreed-upon cash price after a week?

It is not permissible to extend the term in a deferred sale or to convert an immediate contract into a deferred one in exchange for an increase in price. This is known as "debt rollover" or "debt annulment," which is the forbidden usury of the pre-Islamic era (Jahiliyyah). If the buyer delays payment, the price cannot be increased, no matter how long the delay. If the buyer is capable but procrastinating, he is an oppressor. If he is in straitened circumstances, he must be granted a delay. The seller may annul the sale in the event of the buyer's insolvency and reclaim the commodity if it is still in its original state. Then, the seller has the right to sell it on a deferred basis to the buyer or someone else without a prior condition to that effect, so as not to be a stratagem for usury.