What should someone do who ignorantly lent a sum of money with interest, then learned of its prohibition, and the borrower wanted to return the amount in cash or with a mobile phone whose value exceeds the original amount, then the latter returned an amount greater than the debt but less than the value of the proposed mobile phone? And should he return the excess to the borrower, or give it in charity, or use it?

Consuming usury is one of the major sins for which Allah has threatened those who consume it with obliteration and the removal of blessings. He has declared it an open war with Allah and His Messenger, and the Prophet, peace and blessings be upon him, cursed the one who consumes usury, the one who feeds it, its scribe, and its two witnesses. The man's procrastination in repayment does not permit taking usury. The questioner must return the 500 Riyals to him, and his responsibility is not absolved by giving it away as charity on his behalf as long as he is able to deliver it to him.