Sorry, Samson, that I just now saw this - probably too late. I'd guess the only hope for what you have at this point is to heat it up to 180°F (82°C) or thereabouts and make it into ricotta.
Is this your first foray into making cheese? If so, be aware that mozzarella is notoriously difficult to get right -- contrary to the "easy 30-minute" advertising that is so common. (Are you using the 30-minute recipe for mozzarella? Or something else?)
A couple of other comments: using the rennet within a certain time frame might affect coagulation, but as long as we're not talking more than an hour, I wouldn't expect it to be the reason for setting or not setting. What type of rennet are you using, and how much?
What type of milk are you using - store bought, pasteurized and homogenized, or ?? Anything other than raw milk has been subjected to some level of damage; as long as the damage is not too great, one can still make good, even great, cheese from it. But if the milk has been, say, ultra-pasteurized, the chances of success get very, very slim.
MOST IMPORTANT OF ALL: Welcome to the forum! Don't give up now - all of us have had some failures - there's even a lengthy thread detailing many of these, just as a sort of shared pain & encouragement.
This is a great group of folks who will help you figure it out and succeed. The results are well worth the effort!
