Quid pro quo ("this for that"). "Tit-for-tat", "you scratch my back, and I'll scratch yours".. those are also common terms.
You may also be referring to payment for goods or services.
If you give someone something without asking for anything in return it's called a gift. If you do something for someone without asking for anything in return it's called a favour.
I
Ask them to replace it/ return it/ refund you
It means someone receives something in return for something they are doing.
no, to threaten someone is to tell them you will do something but to blackmail someone is to tell them you will do something to them if they dont do something in return.
to serve someone without asking something in return for example helping someone in need for nothing in return.
Yes, it can be considered theft if someone refuses to return your property, as they are unlawfully keeping something that belongs to you.
Coercion. You can coerce someone into doing something
Investment
Give something back means if you take something you must give someone something else in return.
someone who gives without something in return someone who cares about you n always thinks of someone who is in need
A written document giving someone permission to do something is called a "license."