If you don’t have the money for the spraying, you don’t have it. I’d certainly cancel the automatic debit with the bank. If they can’t spray right what makes you certain they can debit properly? I know you don’t want to be hassled by them, but seriously what are they going to do to you for $99? Heck just billing you for it would cost them more and do it. I’d send them a letter and state what you have stated below and tell them they have broken contract with you.