I bought two 6-packs of the Sentinel Spectrum. I paid a total of $144.00 at the vet. I was given the form and the receipt for the heart worm preventative. I mailed everything in and waited for two or three months. I received a gift card in the mail for $7.00, not $25.00. I was given no explanation for the discrepancy whatsoever. Why would anyone go to so much trouble for $7.00? I mailed the gift card back to Virbac and I will never buy another product from this company again. If my vet doesn't offer alternatives, I will change vets.