Sorry to hear about the problems getting the job done. I would continue calling the office requesting an update. If they do not provide one then I would file with the BBB, depending on the company, that may light a fire you know where. If they are owed additional monies then have a partial hold on them.
Until the filter is up and running you can add chlorine but must be very careful with a liner to DILUTE IT! I would dilute bleach in a 5 gallon bucket and then slowly pour around the perimeter of the pool. The size of the pool and testing #'s would be needed for specific quantities.