Shocking Service

We're a wedding service provider, and have been advertising with [URL Removed] for many years without incident. Just over a year ago, we started having mild problems with their billing. More recently, the amount debited from our account has been changing despite our signed agreement with them, and we have been overcharged. The amount invoiced is also not the same as the amount debited which causes problems with our tax returns. We've been trying for months now to resolve these billing issues via email and telephone, but they often ignore us or make empty promises. We've provided them with figures and dates to make it easier for them, and it still isn't fixed. All in all, their billing system and service has become highly unprofessional and unethical.