Time Capsule not restoring or able to browse after new hard drive install

i am trying to help a friend here so going on what they told me as to what happened.

everything was working as it should until they lost the hard drive.

They went to Apple store to have drive replaced and OS installed ( iMac). the technician said that they would have to hire someone to retrieve the data from Time Capsule. could cost $500. to $3,000. to have done.

this is where they called me.

there are two machines that back up to this capsule. one back up works fine to a laptop, the other (iMac) reflecting 619gb of total data, will not restore. nor will it allow us to enter.

my friend said the apple tech disconnected the capsule while it was trying to see drive in Migration Assistant while it was still thinking because they were impatient.

any help would be greatly appreciated. they may have lost their entire family photo collection.