Disgusted with telkom!

My husband and I are incredibly frustrated! He cancelled his telkom account in dec, using the website - and is still being charged. Even though I have since then phoned several times to cancel. I made the mistake of wanting to order a line for data but then cancelled due to shocking service. Have cancelled my order more than once...and I'm now getting messages about invoices etc. This is ridiculous. How do I get this done once and for all?