I bought an item from a Jewish store. After a few uses, I found that it was slightly faulty. I intend returning it, but it will be a while before I can get back to the same store, and I’ve used the item a few times since this decision (as I don’t yet have a replacement).
Does this constitute ribis? May I continue to use it lechatchilah until I get back to the store?
I don’t think there is a “ribis” problem because since your intention was to purchase the item therefore the money given was not intended as a loan. Also since you are still using the item, the usage is worth money and they are entitled to keep your money. Never the less I don’t know if you can keep on using the item because the store are not at fault that it is taking you a while to get back. Every usage causes a slight depreciation. The best thing is to ask them if they mind you using it until it is returned.