Urgent help needed

Query for CA 1-I am a part time management consultant. I was having Serv tax number and regularly did that. Before introduction of gst ,in that and preceding year, my turnover was less than 10 lacs and So, I wanted to apply for Serv tax deregistration. 2- In the meanwhile provisional gst was allotted automatically and the person helping me made me collect and deposit gst (staying that cancellation process for provisional gst registration was not available till that time ). 3-Meanwhile, he also registered me for gst(he said deregistration of provisional gst not being available till that time, must register and then deregistration can be done- he did this without asking me on his own and I have shared OTP trusting he is doing what is best for me) 4-Then, he said that since you are registered and have gst- in number ,now you will have to collect, deposit and file returns. 5-He did that for me ,but ,he didn’t file gstr-1 for October 17-December17. He said it was not possible due to glitch in gst site. He has not done it so far. 6-In the meanwhile ,yesterday I found provision to apply for gst deregistration and applied on line yesterday itself on the gst portal . I also found out that gstr-1 for October to December should have been done by 15/2/18. My questions are (in view of above) 1- what happens to pending gstr1 for October- December? How can I regularise it? (If I am unable to file gstr1 then recipients of services can not get refund which will be an issue.) 2- My deregistration application of yesterday’s is still pending. Will it affect gstr1 filing for October-December and Jan-March? ( I have raised March bills already with gst upto 15/3/18 and nothing is pending to be raised in March ,ie ,this month.) 3- in view of my gst deregistration application ,can I stop collecting gst after the application date ie 16/3/18 ( I will have bills in April only) and stop the procedure of filing returns etc? ?