What is the ruling of Islamic Law on buying a car through an auction, knowing that one of the conditions for participating in the auction is paying a refundable amount, and upon refunding, a fee of 5 dinars must be paid, and the company organizing the auction takes a commission based on the amount paid for the car?

My maternal uncle bought an apartment through an Islamic bank and wanted to sell it to me before he completed the installments. He had paid the bank 5,000 dinars and said to me: 'Buy the apartment from me in return for 7,000 dinars (5,000 paid as down payment and 2,000 as profit ), and you continue paying the bank installments. Once they are completed, the transfer of ownership will occur.' I paid him 7,000 dinars and continued to pay the apartment installments through the same bank via his account until now. However, my uncle passed away and the bank absolved him from the remaining installments. Am I absolved from these installments as well?

A medical book is sold in the market through a distributor. I contacted the manufacturing company, and they said, "There is no exclusive distributor for the book, and you can buy and sell it as you wish." Is it permissible for me to sell the book? Does this fall under the  meaning of the Hadith which states: "One of you must not sell (his own goods) when his brother has already sold (his goods)", or is it considered legitimate competition?

My father bought an apartment through the bank and then sold it to his paternal aunt's children without registering it. The apartment remained in his name without any formal transfer, and his paternal aunt's children continued to pay the installments to him. After my father passed away at the age of less than sixty, he was exempted from the remaining installments. Are his paternal aunt's children exempt from the remaining installments as well, or they required to pay them to the heirs?

Some people purchase grapes before their ripening, or, sometimes, before their formation, with the aim of obtaining their leaves. Is such transaction permissible?

We are a sales company, and we can cause substantial loss to competitors by lowering our prices for two months and eventually forcing them to exit the market. Given this fact, is it permissible for us to outcompete our rivals by reducing our prices or not?

Sometimes, school cafeterias have a surplus of unsold food products. Is it permissible to sell it at a low price or distribute amongst the students, even randomly; particularly since it is subject to rapid deterioration? 

Is it permissible to purchase a watermelon under the condition of cutting it open to make sure that the pulp is good?

I have a portfolio in which I keep my money balance, however, I sometimes need cash so I transfer (100 JDs), for example, to a person`s account and he hands me (97 JDs) in cash. Is this permissible?

I work in cellphones trade by installments and cash sale. Is there any specific percentage determined by Sharia? And am I permitted to have 100% as a profit?