full
partial
10%, 50%, etc.
cash
tax
prompt

give (sb), issue, make (BrE), pay, provide
They'll only give you a refund if you have the receipt.

offer (sb)
refuse (sb)
He has been refused a refund on his air ticket.

be entitled to
You're entitled to a full refund if you change your mind.

ask (sb) for, claim, demand, request, seek
get, obtain, receive

refund for
There will be no refund for cancellations.

refund of
a full refund of the registration fee

refund on
She received a refund on the unused tickets.

refund to
refunds to 10 000 customers across the country

in full
Your money will be refunded in full.

gladly
promptly

to
If you are not satisfied with the goods, the price will be refunded to you.

Refund is used with these nouns as the object:
fee, money