Replacing Missing Aligners?

I paused my Invisalign care during Covid due to high risk health concerns, but I continued my payment plan. I had only received a few of the aligners. I contacted the office to get back on track with the treatment, assuming I would have to start from the beginning, but the office said they no longer have the trays. What would they do with all of those trays? Do they throw them away or send them back to Invisalign? Can Invisalign reproduce the missing aligners based on the first order?