No customer service at all

I'm having a horrible experience with on-air billing services. They 1st sent me threatening messages saying I did not pay whereas they deducted, I made numerous calls and had to entail proof, to which they never responded or confirmed. This month the deducted 2x 5days apart. I made several calls contacted them on the phone and email unsuccessfully. I'm at my wit's end them. The only time they are contactable is when they are selling.