Building demolished by bmc

On 10th July 2010 the building we were staying as tenants were sold to another set of landlord which was part of the family only. On 4th july 2011 they sent a letter saying that the building was weak along with structural report. We all tenants accordingly jointly replied on 17th feb 2011 on the letter saying that the landlord needs to repair the building and we are ready to support him on the same. The landlords were not bothered to repair the building and intentions were to further deteriorate the building by not conducting and repair or maintenance Builder. Over the years nothing happened and since the building was weak one by one all of us the tenants vacated Recently We Tenants had received a general common Letter from Municipal Corporation Greater Mumbai u/s 354 and another letter Appendix - G, u/s 488. In the first week of june 2018 the survey was also conducted by the authorities basis the documents given by the landlord and the authorities just did a formality exercise. The authorities in oct 2018 gave the survey area letter which was disputed by us as the areas in that letter were less. Suddenly just last week (oct 2018) onward the authorities started demolishing the building without any further notice to us tenants and got the building down. We had our furniture and fixtures and some valuable things in the stuff and now there is none of our goods. What action can we take against the landlord and the municipal authorities.