Insurance companies can be extremely rude when they are on the phone to you, it's amazing... They are there to support you when things turn bad, but generally they are mean and snappy. You would think they were better prepared!
When you phone your insurance company, they record everything I do believe, you can speak to a manager and get them to check back on the records - they can see who access your account and when on the system, and they can check the tape of the person telling you $500. Once you get that confirmation, you can do the I TOLD YOU SO dance and wave it in their face, whilst also asking them to counsel their rude meanie staff member to provide a more caring and considerate tone with their customers in future... if you're up to it!!
If it helps you keep your composure on the phone, grab a kids colouring book and pick some hilarious fairy picture - shade it all in nicely all pink and pretty while you're on the phone and you'll be less likely to get too upset. It works for me... shhh don't tell anyone, it's embarassing. ;)