WordStream Deceptive billing practices and contract terms BOSTON Massachusetts

We engaged Wordstream to assist in our online marketing efforts. We completed a 6 month initial commitment and were reasonably happy with the services provided. We did not feel that additional services beyond the 6 months initial engagement would be cost justified. 2 days after the 6 month initial obligation on May 28th, We sent an e-mail to the account manager cancelling the service. The had just charged our card for the next month in advance. Per the initial agreement, the fee was to consist of a base of $1,000 per month and a usage fee which was to be calculated on a percentage of advertising purchased based on their guidance. They have a 30 day cancellation policy. Our obligation should have been the base fee plus 2 days worth of the calculated percentage as no services were provided after the cancellation of the service. Not only did they charge the full amount and refuse to refund the overage, they charged an additional 30 days of the base PLUS the usage fees 29 days later for ANOTHER month in advance. We called and I wrote 3 detailed e-mails explaining our position and they refuse to refund the fees charged to our card.