Hi Diane
At least the OC is doing the right thing in offering to pay your costs. I would get quotes very quickly to replace the items and submit them to the Strata manager and advise the Exec Committee at the time you submit those quotes.
Also, document exactly what was lost due to the contractors and how it happened. That way the Owners Corp may be able to claim from the contractors (although that is easier said than done).
I would then also put a caveat on allowing the contractor access to your yard without supervision to avoid further damage.