Various masaail of trade

Q: I own a shop that sells ornaments, glassware, crockery, etc.

Often, customers pick up items to examine them and then drop them accidentally, causing them to break.

Similarly, customers sometimes place items in their trolley to purchase, but then drop another item on top of the first item, causing it to become damaged. The customer then says that they don't want the item because it's damaged.

In the above two situations, can I hold the customer liable for the item and charge him for it?

Q: In some restaurants, if a person orders a dish and wishes to share it with someone else at his table (e.g. a husband and wife order a dish and both wish to share it instead of ordering separate dishes), the restaurant will charge the second person a ‘plate sharing fee’. If the second person does not pay this fee, they will not be allowed to share in the dish of the first person. In Islam, is it permissible to charge a plate sharing fee?

Q: My parents take products which they pay for later.

1. Sometimes they pay a few rands extra out of love. Is this fine?

2. Sometimes, I wish to give them a discount when I’m sending them the account (as they sometimes help me to clear stock that is close to date). Can I give them a discount after they have taken possession?

Q: I ordered an item from overseas. When ordering, they offer you various shipment options, such as couriers, post office, etc., with various pricings.

1. Does this make me responsible if the post office loses the item, because I chose who I want to deliver the item to me, making them like my wakeel to accept the item and transport it to me. However, on the other hand, the seller still remains in control of the shipment since they sent it. For a lost parcel the seller will have to contact the post office and submit the claim, etc. not me.

2. The parcel disappeared, it seemed to be lost. The seller sent a new item by courier, which reached me within a week. The seller (non Muslim) will make a insurance claim for the 1st item from the post office. Can I use this 2nd item they sent me?

3. A few months later the first item arrived in the post. However customs want a payment of R1000 to release it. I need this shipment to be sent back to the seller because I have already received the 2nd parcel they sent, and this is extra. Who will have to pay for the return shipping and customs fees?

Q: I work in a shop. One customer mistakenly gave me more money than usual. I didn't return his money. I spent that money. Now I'm feeling guilty about that. What should I do? Please help me...

Q: A seller charged me £1 for an item. The next day I purchased the same thing but this time he charged me £2, citing that he made an error the previous day. Do I owe him £1?