Lost and Stolen items

Q: I own a shop. Sometimes, when people buy goods from me, they leave it in the shop and don’t collect it. Is it permissible for me to re-sell those items?

Q: I do transport for a company that does packaging for various other companies. I do not know the details of their agreemants. I was given a bag of products from the company as they were moving warehouse. Also the balance of the products were returned to the companies for whom this company offers their services to. Can I use these products or is it better to return them?

Q: Few years back when I was going home from office at night I found Rs.100 on the road. I was not so much aware of the Islamic path at that time and I spent the money on myself. But now I feel its a big sin and its hurting me and making me feel guilty. Please guide me what should I do now. May Almighty Allah bless us.

Q: If a person stole money from a person then another person stole from the original thief, Islamically does the thief get compensated in the next life?

Q: I work in a shop. Sometimes, customers forget their change and sometimes also forget their purchased items. What should be done with their change and items?

Q: If clothes were stolen from a store and now someone wants to repent from this, how does one pay back the store?
If the owner was not known at that time and don't know if the owner is still there, then what action does one take?

Q: While passing through one of the farm towns, a guy at the garage was selling avokados in a bag. When I bought that, he offered me suger cane as well. Only after I bought it and returned home, did I realise that he only had one sugercane. So I perhaps thought that why was the avokados in a bag which he had lots of (in different bags), but he only had a single sugercane. I perhaps thought that maybe he got the single sugercane by walking past one of the farms and taking it with out paying for it, which he sold to me. What should I do in this case, if I doubt that the sugercane was perhaps stolen?