You clearly signed the contract, and barring some highly unlikely language that explicitly stated that it had to be hand delivered and (possibly) no counterparts etc... it's also going to be considered "delivered." Sorry for the blah blah blah blah. But as others pointed out, enforcing it is an entirely different matter. There can be some nuances depending upon where you live, but at worst there might be a non-compete keeping you away from the same industry for a portion of time, and you would have mentioned that by now. Non-competes are virtually unenforceable in many jurisdictions anyway (including here in California, unless you're selling a partnership stake or a few other small exceptions, such as when trade secrets are relevant). Don't be a dick and just work things out with them.