If your feed is valid, you may want to try "burning" the URL with Google's free FeedBurner service: http://feedburner.google.com/. Then, try using the URL generated by FeedBurner with your Blidget.
Removing the "Get Widget" button:
With a Widgetbox Pro subscription, you have the option to hide the "get widget" button. To do this, go to the widget's Details Page (e.g. http://www.widgetbox.com/widget/maukie-the-virtual-cat), and uncheck that box that says "Include Get Widget button". By doing so BEFORE you install the widget, the "get widget" button won't be included in the embed code that you paste into your website.
Keep in mind that if you've already installed the widget with the "get widget" button included, you'll need to remove the embed code from your site and then reinstall the widget after unchecking the box.
How Do I Cancel My Widgetbox Subscription:
To cancel your Widgetbox Pro subcription, follow these steps:
Login and click on "Your Account" in the top right corner
At the very bottom of the page next to "Delete Account", click "Cancel Pro Subscription"
This will ensure that you won't be billed again.
How Do I Cancel My Mobile App Subscription:
To cancel your Mobile App subscription, follow these steps:
Login to Widgetbox and click on "Dashboard" at the top
Click on "Your Mobile" from the tabs below the dashboard
Select the mobile app you'd like to cancel
Scroll all the way to the bottom of the page and click on "Delete Mobile App"
This will cancel the subscription, and you'll have the option to delete the app all together.
How Can I Receive a Refund For My Subscription:
Payments for Widgetbox subscription services are non-refundable. This is outlined in our Terms of Sale, which all customers must agree to prior to purchasing. These terms are available for review here: http://www.widgetbox.com/info/legal/terms-of-sale/