L.M.
Talk to the provider. Ask her "what contract are you referring to? I have never see one from you" and then proceed depending on her response. Most do have a contract and some ask for a week or two in advance so if you quit without notice you still have paid them. Many have a probationary period where a week or two for adjustment/trial period where either the parent can cancel without notice or the provider can sever without cause.
Why did you opt to cancel so soon?