Hosted Exchange 2010 and iPhone issue...

One of my clients setup his own personal hosted Exchange 2010 account two plus years through GoDaddy. At that time he had an iPhone 5 and connected it to the hosted Exchange 2010 account. At some point, about 18 months ago, the password needed to be updated but he never did it. Thus, syncing stopped between his iPhone and the Exchange 2010 server; however, he continued to put in contacts and calendar entries in his iPhone. He apparently never noticed that his phone was not syncing. This past weekend he backed up his iPhone, bought a new iPhone 6 and attempted a restore. At the point of restore, he realized his hosted Exchange account not properly syncing. He corrected the password issue on the hosting server and entered into his phone. After syncing, all of the data he entered in the last 18 months on his phone was deleted (he still has the backup and can do another restore) as it appears the server synced data from itself to the phone and not back from the phone to the server. Has anyone ever dealt with this issue? Is there a way to force the sync to occur from the phone to the server one-time so that the new data gets synced with the server?