If you don't have a business/federal ID # in order to sell to the refiner you called you can try David H Fell
That is who I use when I have over 500 ozt (actual silver content) of sterling scrap to sell (which I did just a couple month ago)
Here are their payout rates on sterling scrap
less the 50 ozt (actual silver content) 90% plus $35 assay fee
50 to 99.9 ozt (actual silver content) 91% plus $35 assay fee
100 to 499.9 ozt (actual silver content) 92% no assay fee
500 to 999.9 ozt (actual silver content) 94% no assay fee
1,000 ozt or more (actual silver content) call for quote no assay fee
They normally settle (pay) in 2 - 3 days - day after receiving the scrap
https://dhfco.com/
Call the Rio Rancho New Mexico office (that is the actual refinery) - (505) 994 - 0010
They will send you forms to fill out to send back with your shipment
a form for what you are shipping & method of payment --- a tax form (they do not 1099 you as long as you don't send more then $10,000 scrap but they still need the tax form filled out for their records)
I have used them several times & have been happy with their service
Kurt