You stopped service which is good. Is her property out of your way? If not, visit it everyday, knock on the door, demand the money...Id do that for five or so days...then I would come up with a letter saying 'pay me this, plus this late fee by this date or meet me at small claims' and be sure to mail it via Certified Mail that way she has to sign that she received it. Be sure to take the mailing receipt with you to court, along with any and all documentation of her (contract, receipts, invoices, letters, etc.) Just my two cents.