"Reference letters in the required format are necessary, please try your best to get them. If after all efforts you are unable to obtain a work reference letter, then you should provide a solemn declaration / affidavit explaining in detail why are you unable to do so. The officers at the VO are aware of the fact that different employers have different policies towards issuing such adhoc letters and may not cooperate in issuing such a letter. Please do attach all your employment records with the declaration. I was unable to obtain a work reference letter from one of my employers and did the same. However please bear in mind that the final decision rests with the visa officer handling your case."
U can submit below Sample affidavit for the alternate work reference/job description letter:
Sample notarization
Date:
SOLEMN AFFIRMATION
I the undersigned, (principal applicant), residing at ___________________________________, hereby solemnly affirm that from (date) until (date) I was employed by (company name) as (job title).
I worked (number) hours per week and was paid (salary) (weekly, monthly, yearly).
My main duties consisted of (main duties).
Main Duty 1
Main Duty 2
Main Duty 3
Main Duty 4
and so on and so forth.
I am unable to obtain a letter with the job description from my employer because the HR department doesn't provide any such letter with the job duties mentioned on it. The only thing they provide with is an experience letter with the designation and the tenure of the employment mentioned on it, that too at the time of relieving. I have that letter and I shall enclose the notarized copy of the same.
______________________
Signature principal applicant
Good luck...