Relieveing letter not issued by company

Dear sir 

I was working in MNC company Dubai , feb 2016 i came to india for my wife delvery, same time after coming to india and i have found opportunities in india of same company in indian branch

consecutively i have applied and called for interview and i have been selected and was given offer letter.

after that i have send resignation letter to dubai office and requested them to relieve me and consider my one month notice period in annual holiday and requested them to debit my leave salary.

mean while HR from indian branch has already informed to HR in dubai branch anout my recuritment and no reply/objection came from DUbai HR , indian HR has issued me offer letter.

My boss in dubai has not aggreed for my resignation( actually mydecision to come out of dubai is my dubai boss due to his harassment).

Dubai branch has not give me relieving letter till me joining date , but indian branch was very strong in my joining date.

i joined in indian branch in may 2016 in bangalore and i was there for 2 days and then sent to boroda location

after working for 15 days  ,  my new indian boss called me for teleconference with dubai boss and dubai HR for relieveing letter

we all had telecon , there my dubai boss informed that he was having full trust on me and , i am the only person certified to handle soem dirricult litigated projects , but unfortunatle it has gone like this then they told we will issue Relieve letter

then my indian boss and indian HR told me that u need to come and join once you received relieving letter it may take some time

then i came back to coimbatore waited for one week  called dubai boss he told it is with Hr , when i caleed HR she never pickups or respond to my mail , or whatsapp

it polonged like this for 3 months and then i got pressure from indian team to resign the job or we terminate you by attendance lacking

i was comfused and then taked with my indian boss to help ,me, he told resign now after six months or one year we will hire you by the time you work in some samll company.

i asked him for relieving letter he has aggreed and request me to send mail about resignation and request for relieving letter

i have send to indian HR and my boss , they asked me to credit back my one month salary which they have paid me ,

i have credited and later i waited for relieving letter for 3months i am keep one sending mail to indian HR and boss not replying

once indian HR picked up my call and she said that dubai team is considering me  as abscond and so we also consider you as abscond

so it is difficult in gettting relieving lettter

so i decied to send lega notice through a lawyer and my lawyer send first through mail by scanning the legal notice the recpient in the mail are dubai hr and indian hr and copy to south asia head of my company  who sits in bangaore

hard copies send through registered post one to dubai HR,one to indian HR and one to south asia head with acknowledgemnt card

south asia head has received it and acknowledgement card came back to my lawyer

and other two are still not received by them al most 21 days over

in legal notice my lawyer have given that due to harrassment i have wish to come out of dubai team and however after reciveing offerltter form india i have resigned and it was officially informed to you

but due to false committment of your company my client is jobless and made artificial break up in my career so he has made a clompensation  for sum of RS 10000000

and issuance of relieveing letter by 7 days of this notice  else we may move to court

no my question is ?

they have recived legal notice through mail all three parties ( dubai team , indian team and south asia head before 21 days ago, 

hard copy received only by south asia head, othe team still not received.

Why they take delay in reply?

only they will reply on receive of hard copy or legal notice has some validity time

or advise what i have to do next

pls hep me

)