it's interesting how people interpret law the way it suits their needs. once i've got a notice from a well-known sponsor back at the day expecting me to take their links down like yesterday. all without even notifying their affiliates about any changes.
what does the law actually say: replying to a DMCA notice has no deadline. the default setting for most of these applications is 14 days though they can range between 7 and 30 days.
apart from the URL in question, the most important part of the DMCA notice is:
"I have a good faith belief that the use of this material in such a fashion is not authorized by the copyright holder, the copyright holder's agent, or the law;"
so guess who's getting richer whenever one visits a lawyer?
calling somebody a thief in public actually allows them to sue you for defamation. personally i would suggest you to apologize and take an apology back, get the money as a sign of good faith and bury the hatchet. too much drama lately and not much business around...