They avoid providing service but will NOT STOP calling once you cancel.

Not only do these guys only respond to a request for help a month + after I submitted it 3 times, but they cancelled in 24 hours, sent on the confirmation and have been (apparently) dealing with cancelling the contract ever since.

Then, they finally actually respond to the request for help AFTER I have cancelled...great stuff.

And they've been calling me 3 times in a row while I am in meetings, refusing to accept that I don't work for them.

Who do you think you are? I hang up on you once, twice and then a 3rd time you're still calling me in the same 3 minutes?

Sort out your workflow. Whomever did it ripped you off and is destroying your business. Get a proper consultant and testing in because it is absolutely terrible work.