It might be worth a call into VMWare support to see if they can help you determine if the failed migration is consuming any extra space and how to roll that back.
You can also take a look at this article and see if you can get some help with zero reclaim
https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.storage.doc/GUID-B40D1420-26FD-4318-8A72-FA29C9A395C2.html
You can also take a look at this article and see if you can get some help with zero reclaim
https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.storage.doc/GUID-B40D1420-26FD-4318-8A72-FA29C9A395C2.html