Hi M,
I'm sorry to hear that you haven't been receiving the best of support and that you had to return your product to the retailer. I unfortunately won't be of further assistance as I will be out of the office for considerable time. I don't know anything about a filter on our LCD, which, as you suggested, may be the root of the issue.
Once again, I'm sorry we were unable to assist you with that.
Best of luck,
Nick