Dear Mr. Gaurav,
Principally, the principal employer can’t held responsible for delay by the contractor in PF-ESI contributions. Even in a recent case law, Hon’ble court has given judgement if the contractor has separate PF code than PE can’t be held responsible (attaching the article, which I recd from here only).
I would suggest you to deeply check and monitor whether the contractor is depositing the contribution as per dedcution or not. Many contractor deduct higher PF-ESI and deposit less. Even in online process also they do by modifing the ECR, days and wages. Sometime in order to show to the PE they prepare online ECR with actual wages in r/o all employee than cancelled the ECR and prepare another one with less contribution. In such case if any workmen file case in labour court and make party to the PE as well, than you have to appear to the labour court for the hearing.
In such case if the contractor is unable to deposit the short fund (contribution) than you may be asked to compensate. In order to overcome to the situation at time of contract completion before making final payment, first ask the contractor to complete all statutory components. Wait till all employees get their fund (either withdrawal or transfer), Bonus, Gratuity, Leave etc pymt. Than ask the contractor to submit NO DEMAND CERTIFICATE (which he will obtain from getting signature of all employees).
You can demand the same certificate from the contractor to safeguard your company in the future as well.
Hope you will agree with my point, fellow members can put more light on the matter.