Topic - is relieving letter required for hotel jobs in dubai?

I worked in an organization for the last 4 years in India. I have resigned and its been a month since the time that i have not received my relieving letter/ experience letter. When contacted my HR, they have said that the whole process will take one more month. In this interim i have started getting offers from other hotel companies in Dubai. What do i do as i have barely 10 to 12 days before joining them ???????? Will they take me without a relieving letter or is there any other way of proving it to my employer that I have worked for 4 years in this organization like my appointment letter and salary slips?????