Disappointed parent

How long does it take for contract of enrollment to get terminated. I’ve been contacting sparks schools from January and still now, they haven’t terminated my son’s contact. To my surprise I’m still getting invoices. I’ve sent numerous emails with no response. When I call the school they only answer I get is send us an email. I’ve been sending emails and I’m not receiving any feedback. This is very disappointing and tiring because they are quick to send invoices without noticing that my son has never even attended their school. If they were keeping records they should contacted me regarding my son’s absence but no their finance department is more effective than the school itself. please respond to emails so we can get this matter sorted ASAP