Company asks to submit resignation from one company to transfer all employees to new company by same directors

Sending Greetings to all Seniors. Sir, I am working in a construction firm since last 12 years as an Liasoning Executives. I am getting a salary direct in my salary account in bank. In last year they started one more construction firm to cater Slum rehabilitation projects.
Sir, yesterday our HR called us in her cabin and told by mistake company deposited cheques in our account from new firm from April 2018 , so now all of you submit RESIGNATION to company, then will re appoint to all of you in new firm?
Sir, now we all are totally blank; please advise what we have to do? Note: (both company is a family run company & run by north Indian Marwari family and the all four Directors are same, Registered office is a same and run under one roof. and they never paid any gratuity to previous staff who worked more than 5 years.)
waiting for your valuable advice.

Whose cheque was deposited in your salary bank account is immaterial for you. What is important for you to ensure is why this resignation and that also for a "mistake" committed by the employer? When you say that there are different entities but under the same management team, you can smell a tricky act by the management to avoid payment of gratuity etc. This happens wherever this kinds of family run establishments are there. From the legal point of view, and for the purpose of deciding the applicability of various laws like Provident Fund Act, ESI Act, Bonus Act, Gratuity Act,Industrial Disputes Act etc, the employees in all the concerns under the same management will be clubbed together. Therefore, there is no meaning in saying that a few are in the new company and therefore, should resign from the old company and the new company will issue new appointment order etc.
Please tell us under which company's member Id that your PF is being deposited? If you were under the new company since April 2018, they should have remitted your PF in the new company and you should have got a new member ID. Again the employer or the HR should have initiated the transfer of the PF from the old one to the new one. Above all, there should be a clarity on the length of service, how is it going to be treated at the time of your superannuation or resignation?

Dear B Rajesh
Prima facie this smells some deception. If cheque is wrongly issued than may ask for refund the amount or intimate the bank..no stretch of imagination justifies asking for resignation.
Shailesh Parikh
99 98 97 10 65
Vadodara

Thanks to Madhu sir & shailesh sir.
Referring to Madhu sir's reply, i have to add since last 12 years company neither generated our PF Scct.nor deducted any amount for PF, ESIC or any other perks. Just received neat salary and bonus at Dipawali. No any other pearks.