Invoiced a Month AFTER cancellation

If it were possible to give Accerl**** a negative score, it would be -10!!! I cancelled our subscription on 21 May 2019, I confirmed the cancellation on 21 June 2019. Low and behold the illiterate bunch of idiots that work there send me an invoice on 23 June 2019. This "organisation" is a NIGHTMARE to deal with, stay away at ALL costs!!!!