When someone offers you a service or product, do not say you refuse.
Saying you refuse indicates that you had a prior obligation to accept the service or product being offered, and you have now defaulted on your “prior obligation”.
For example: do not refuse a test, just decline the test. If you refuse, the one making the offer will continue as if you have now defaulted on a prior “obligated contract”.
The correct response would be to “decline the offer”, as this shows this is the first time the offer has been made, and therefore there cannot be any prior obligation within a contract to accept.
If they persist, then they are without honour and you can make a counter claim against them.
Refusal