Does it sound natural to say " get a refund of the duty ."?
1. You know sometimes after you purchased something and normally you pay the duty for the item as well , but in some countries , you can get a refund of the duty . So here's my question :
How should I say it in English ?
Like
" where can I get a refund of the duty for the lipsticks I just got ?"

2. What does " there's no ambiguity..." mean?
Can you give me an example using this phrase ? And does it sound too formal so that it may sound weird in daily conversations?

Thanks a lot for answering these questions !

Question

Does it sound natural to say " get a refund of the duty ."?
1. You know sometimes after you purchased something and normally you pay the duty for the item as well , but in some countries , you can get a refund of the duty . So here's my question : 
How should I say it in English ?
Like 
" where can I get a refund of the duty for the lipsticks I just got ?"

2. What does " there's no ambiguity..." mean? 
Can you give me an example using this phrase ? And does it sound too formal so that it may sound weird in daily conversations?

Thanks a lot for answering these questions !

Answer

1.  Yes, that sounds natural.  You can also say “Where can I get a refund of the duty I paid on the lipstick I just bought.”  2.  “There’s no ambiguity” means “the meaning is clear, and there is no uncertainty.”   “Ambiguity” is not too formal to use in everyday conversation.  Example:  A professor might say:  “Just so there is no ambiguity, let me repeat myself:  The deadline to turn in the assignment is 5 p.m. on November 8.  Any assignment turned in after that deadline will not receive ANY credit.”