As explained, up to the point when you withdrew your interest in the property, you were in the hunt...you state, the property remained "active." Was this "active" or "active with contract?" There is a big difference, with "active with contract" allowing continued buyer interest until all contingencies are satisfied.
At this point if the new buyer is under contract and scheduled to close, there's really not much you can do at this point. They can't be under contract with two buyers. So it sounds to me that your contract fell.
Keep in mind the listing agent is looking out for the best interests of the seller. That means continuing to market the property in case the first contract falls through due to whatever reason (inspection, appraisal, loan, etc.). But the seller can't accept a new offer until the first contract has fallen through. Again, talk to your REALTOR!