First question would be "were you a bad tenant"?
Assuming that your current landlord had contacted your previous landlord,
otherwise old landlord wouldn't know who to call, they would have been
responding to a request for a reference. Obviously your old landlord can
report information as they see fit and your new landlord can take it into
consideration. Old landlord has a responsiblity to be accurate and not
inappropriatly retaliatory. Whether you are at a contractural point with
the new landlord that you have a contract established would depend on
what has transpired.