550-550-540- Badly need your help experts !

First of all, its a long post. Apologies for that . I just wanted to express the whole situation so that you (Experts, fellow gmat takers) can understand it clearly and suggest me how to get out of this pathetic condition

I’m a nonnative speaker (from Bangladesh). I have given GMAT thrice and scored miserable 550, 550 and 540 (considering my target score of 750 ). My main weakness has always been verbal. After the last exam, I’m feeling clueless as to what to do, where to start again and most importantly where to finish

Experts, fellow students, I REQUEST you all EARNESTLY to read my detail, and help me in anyway you can

Preparation first phase (score 550, Q 42, V 24)
Preparation started – February, 2013
Exam date- 15th December, 2013
Prep duration- about 8 months (could not prepare in June, July due to work pressure)
Study hours – avg 16-18 hours/ week

Materials used- Quant
Concept :: Mgmat 5 guides
Practice :: scattered questions from gmatclub, OG 13 (for practice)

Materials used - Verbal
Concept :: Mgmat Sc, CR bible
Practice :: Scattered questions from gmatclub, OG 13 and gmat question pack 1 (SC and CR) (practice)

Mock test
Mock 1- 23rd July, 13 - gmat prep - 600 (Q 40, V 32)
Mock 2- 11th Oct, 13 – gmat prep - 550 (Q 42, V 23)
Mock 3 - 22nd Nov, 13 – gmat prep– 480 (Q 33, V 23)

Major mistakes I made in the first phase ( as per my understanding)
1. Did not complete official guide and verbal+ quant review
2. Focused more on attempting difficult questions (mostly from gmat club) than on mastering easy and medium level questions.
3. Was ignorant about my errors
4. Got confident after getting 600 in gmatprep. Started believing that just continuing study for another couple of months will get me to 700+ level.

Preparation 2nd phase (score 550, Q 44, V 23)
Preparation started- June 2014 (Left my job to concentrate more on gmat)
Exam date- 14th January 2015
Prep duration – 7 months
Study hours- avg 35 hours/week

Materials used- Quant
Concept :: Gmat club math book and mgmat (revision)
Practice :: Completed OG 13 and Quant Review

Materials used – Verbal
Concept :: Mgmat Sc (revision)
Practice :: OG 13, Verbal Review, Gmat question pack 1 (SC and CR), gmat prep CR (a collection of 108 gmatprep questions found in gmatclub), gmatprep SC collection by sondenso

Mock Test
Mock 1- 27th Oct, 14 – gmatprep exam pack 1 – 660 (Q 48, V 34)
Mock 2- 25th Nov, 14 – gmatprep – 640 (Q 48, V 28)

Major Mistakes in 2nd phase (as per my understanding)
1. Did not prepare error logs.
2. Did not spend enough time to master questions. Just rushed to complete many materials
3. Hardly revised concept materials or erros before exam.
4. Did not sleep properly the day before the exam and felt tired during exam.
5. Did not have concrete strategy to tackle different type of questions.
6. Did not leave questions strategically during exam

Preparation 3rd Phase (Score 540 ! Q 41, V 24)
Preparation started- February, 2015
Exam date- 13th July, 2015
Prep Duration – 6 months
Study Hours – Avg 35 hours/week

Materials Used – Quant
Concept :: Mgmat 5 guides, Gmatclub math book (revised both)
Practice :: OG 13, Quant review, Previous CAT questions (created full error log consisting every question I made wrong or got correct accidentally)

Materials Used – Verbal
Concept :: Egmat (Verbal live prep)
Practice :: OG 13, Verbal review, Previous CAT questions (Created full SC error log)

Mock Tests
Mock 1 - 800score.com – score 620, Q 38, V 35
Mock 2 - 800score.com – score 710, Q 39, V 48
Mock 3 – 25th May- Gmatclub test – score 500 Q 32, V 26
Mock 4 - 800score.com – score 680, Q 40, V42
Mock 5 – 10th June- MGMAT free test – score 580, Q 42, V 29
Mock 6 - 24th June –Veritas Free test – 610, Q 44, V 30
Mock 7 – Gmatprep exampack 1 (fresh)- 620, Q 45, V 30

Mistakes in 3rd phase (I’m not quite sure, but can be the following)
1. Not preparing error log for CR and RC
2. Not revising the existing error logs properly and mastering them
3. Not revising the concepts to the level of crystal clarity

I have attached the Enhanced score report (ESR) for the last two exams. I believe it will help the experts to get into my weakness more.