Mr Water Delivery delivers to DUPE you into payment

Mr Water Delivery quoted me per email, stating they needed payment and a confirmation to go ahead before delivery. I as the property owner, gave neither a confirmation nor any payment. The company showed up regardless and delivered water to the tenant. I called the office once I learned of this, and they assured me that it was a mistake on their part and that I would not be billed. Now, Mr Water Delivery have changed their tune and are trying to get me to pay a minimum of 50% of the bill. They have sent harassing emails, sms's and phone calls. I will have nothing good to say about this company and warn future prospective clients against dealing with them, as they are now scrambling to recover massive debt, which is not my problem. STOP DELIVERING TO CLIENTS WHO HAVE NOT PAID !! STOP DELIVERING TO CLIENTS WHO HAVE NOT ORDERED !! Basic business principles, which are not my concern. Further harassment will force me to pursue this legally.