I have recently bought a car and it has Axis Bank fastag but the previous owner is not responding and I am unable to contact him, can I deactivate that fastag on behalf of him?

No, You cannot surrender the tag on someone else's behalf. The previous owner only can surrender his tag.

You cannot Deactivate Axis Bank FASTag behalf of Him. You can easily avail new FASTag on Same Vehicle with Other FASTag Issuer Bank.

if Existing FASTag in Blacklisted & it's not allowing to Get New FASTag than Follow the Steps :

1. Go to Any Nearest FASTag POS or Toll Plaza
2. First Activate Your FASTag on Vehicle Chassis number
3. After FASTag Activation - Request for Vehicle Number Update.
4. after Successfully Activation of New FASTag your Vehicle will have Active Tag ID with that. So Vehicle Number will be Updated.
5. Don't Try to Get Directly FASTag on Vehicle Number if it's in Blacklisted Existing FASTag.

FASTag VO Technologies