Hi Friend,
This seems like a case of misunderstanding on the VO's end....and some fault lies with the Letter u wrote...
Do not panic, start collecting proof of what you can show..
Draft a cover letter explaining (very very politely) tht Probationary Officer is ur Actual Designation...Also explain that a PO in an Indian Govt. Bank joins as Scale 1 officer and during the 2 years of Probation, he may be allotted to any department and allotted a wide range of tasks. Which in ur case was primarily Supervision of Bank Clerks. So the Designation is PO, the job duties assigned to u was Bank Clerk Supervision which involved (insert details here). VO seems to have become confused primarily bcos of ur reference letter wording...
Now attach all possible Official Docs that you can obtain.....
a. The person who signed the Original Reference Letter- Try to obtain a revised Reference Letter that mentions the same thing as the Cover Letter that I mentioned above and giving that person's contact information (possibly on Official Letterhead)
b. If possible, try to obtain a 2nd reference letter from one of the Clerks that you supervised, also stating ur duties as above and giving his contact info..
b. Is there any Advertisement that mentions some details of Job profile of PO in Allahabad bank? Like there is one such advertisement for SBI PO where there is a section called 'Career Path' mentioned->
https://www.sbi.co.in/portal/documents/44978/7348676/SBIPO-2015-Full+English+Advertisement.pdf/fa1e559b-0504-4df6-9d11-534790f1dd95
If it exists, attach to ur application
c. Any Job Description mentioned in ur Offer Letter, or on Bank Intranet system- that'd also help
d. Any work emails that give an idea about ur day-to-day duties...
Seniors can chime in with additional details as they feel....Remember the more documents u provide, the stronger ur case becomes....Good luck and Wish u the best!!