Illegal termination of employees after the company takeover

My company was taken over by another company. The management of the new company assured us, old employees, that we won't be terminated.

My visa got expired on the first week of November 2017. So I asked my boss about the renewal and he assured me that it's a long process and might take time for the renewal.

On the 1st week of December, I was called along with some other staff to the head office, got informed that they are not going to renew our contracts and we have to stop going to work.

I have an unlimited contract. The company did not give us any notice in advance nor did they make us sign on any papers and we did not receive any termination letter. In this situation, I would like to know our rights as per the labour law.

I am still searching for a job and I have a loan with the bank.

Appreciate your advice in advance.