GMAT Strategy

Hi Experts,
Before giving the bad news, let me list my last 2 mock tests results , the tests which I took this week :

MGMAT full test : 710 ( Q50, V36) --- 28th Jul
Gmat Prep : 730 ( Q48, V42) --- 29th Jul

Also please note that my other mock test results were between 690 to 730 in the past 1.5 months

And my real GMAT score today : 640( Q48, V29) . This is lower than my past GMAT score : 660 ( Q50, V29).

I am not really not understanding what really went wrong.

Analyzing what really went wrong with verbal today :

1. 1-20 questions : I felt that I am going fine. But finished in 45 mins ....there was a disturbance in between when there was network issue and I was at the 12th question(2nd RC 1st question), but I was fine ( at least thats what I felt .. in fact I got extra time to think for sometime as the screen hanged in front of me and there was no time loss because the clock stopped ticking.. I could think about the question seeing the screen)
2. But as I was late by 5 mins when I started the 21st question , I had to randomly mark Q 21, 22, 23 , 24 as (c) in all cases , as these questions were from the 3rd RC. May be I did the blunder here. Not sure.
3. Other questions for CR , SC were fine... but I think I randomly marked the RC again ( 3 questions as C) when I was at the questions in early thirties. I think this might be another blunder ?
4. I skiped 38th and 40th question ( both were CR) as I was short of time

But whatever be the case, I think skipping 2 RCs cant bring my score down to 29!!!!! Can it ? But I did the same many times in the mock tests , randomly marking (C) for the 3rd and 4th RC, but still managed to get 35 in verbal.

My questions to you on my verbal disaster:

1. Please tell me what you feel about my performance today. Do you really think that I still need to work on the basics,or strategy was the issue for me. If you feel that I had a issue with the strategy, what were those issues

2. Have you come across any other students who had such a difference in scores between the mock tests and real tests. If yes, what were their issues? Can such issues be rectified in 1 month by an a student who is working( because I cant take leave next month)

3. Please advice me what next steps should I follow. If I want to re-take the exam on 1-sep, can I get 40 in verbal(I will take care of Quant and make it 50 at least in 1 month) Do you really doubt my preparation ? Do you advice me to retake after 2 months instead of 1 month?

4. If I re-take in 1 month, please help me with the steps as to how I will prepare this month.