If government shut down internet service even on fixed line connection then there will be complete internet blackout in the country and in that situation we cant use bitcoin.
I think this is also one of limitation of bitcoin that we need internet to use it.
This kind of situation has more things to consider, the banking system, telephone and cash will be much more problematic when the internet network is down. Is your country currently experiencing a cash currency crisis? If the banking system is fine and still operating as usual, this is another problem your country has deliberately created.
For bitcoin problems, there may have been a lot of suggestions and input given by people in the comments so that you can still use and access bitcoin. Internet outages are a much bigger problem where all network communications will be completely shut down, usually to limit any communication to other countries and this has happened in China.