We've already tried email campaigning and cold calling.
Without knowing what you've sent or done it's hard to know what to advise. If your efforts are all about trying to get in front of someone to say look at my stuff and the and the features it has that's an up hill battle and won't be very effective. There's ways to warm up the leads with social media if they are using it. Look for ways to provide value and build relationships with the decision makers and the gate keepers. A sales coach might be able to help with ways of getting past the gate keeper.
