Can you help me with below and let me know If interest in this situation is fine:

To prevent trading on margin, you would need to ensure you are solely using your personal funds that you deposited to trade. At this time, as the margin account is designed to allow you to borrow we cannot restrict this feature.

As well, please note that for margin accounts, Questrade will not automatically exchange currencies. You must initiate all currency conversions, so if you buy U.S. stocks and you do not have enough USD, you would be borrowing the money from Questrade. You are charged interest on the amount you borrow.

This borrowing is in principle forbidden usurious borrowing, but you can take the money not in the name of borrowing, but with the title of saving the money from the hands of the infidel, so you take the money and own it, and since you are not able not to pay it, it does not harm you if they take the money from you forcibly with the extra.
However, it is not recommended to get into such deals with no need.