No installation - still getting invoices months after

I never received installation and decided to go with openserve. After canceling via telephone calks about 20 times i am niw receiving invoices for the installation that i did not get. Worst experience ever. Ive even tried calling and emailing again to ensure this issue is resolved but the line either cuts off or i am put on hold for 30 minutes plus... i am lost at what to do.