My friend Abdullah told me about a multi-level marketing company in which after investment we can get a profit for 730 days and we can get bonus by referring others. I said that such companies commit fraud. He assured and gave me his personal guarantee for safety of my investment. The company gave profit for few months and then stopped. They had been making various excuses for which Abdullah replied that the company was undergoing an update. Now after about 1 ½ years, there is no profit and no refund. In this scenario, when Abdullah has given me his personal guarantee and return of capital amount, is it permissible for me to demand money from him in Islamic and Sharia terms, and is it my right to ask for a refund?