How to pay gst if company delays pmt for contractual work

I have done some contractual work for govt deptt and company is delaying my payment by 1-2 year. So how can I pay my GST for the bill that I have given to company after doing work but getting delayed pmt generally after 2-3 year.plz advise because I have to pay GST from my pocket because I have made a bill with GST and submit to govt deptt. Is there any way to delay the GST PMT untill and unless I got pmt for my work/bill