Blockchain Payment receive api While using blockchain receive payment api, what if some one send less then require fund or some one send extra fund on same one time generated address.

does fund will automatically refund to sender or not ?

what to do if i want to refund that amount back to user who send less fund or double fund on that address?

any one have information regarding this?
I dont know which api you are talking about , but i am this much sure that ones your transaction is minned and updated in block you cannot revert it or refund it. Blockchain data is immutable. If you want to restrict your client form sending low or high then you have to use some business logic on backend of your code also using JS logic on front end when user inputs the value will help you alot