I do order my heartworm meds from Allivet because they have the best price. Their phone service is fine and they contact my vet to approve the prescription without issue. But the website is TERRIBLE! It loads horribly slow, requires you to re-log in at ever step, and msot areas of the site return "invalid login" when the correct email and password are used. I think you're better off just calling their 800 number.
Dear Joe - We apologize for any difficulties that you have encountered. We will investigate the issue and resolve ASAP. Our customer service reps are on stand by ready to assist with any questions or concerns. Thank you!