Dear Saunee,
If the contract has not terminated yet, pls don't release the pymt. Hope the contractor is making labour pymts.
You can deduct the PF contribution amounts form their bill alongwith some administractive charges. The PF of contractual labour can be deposited into PE PF Code.
If the speed post returned undelivered, I will advice to send your queries, letters, reminders thru email/s ids of respective person.
You can take some consultant's advice to close the matter asap. Prolonging it will create more trouble/s for you. Bcoz the matter can lead more legal implication as well (o/s payment to contractor, other statutory payment to labour like EL, gratuity etc.)
However, in connection to the PF notification, I was little bit confused. There was no notification issued by the EPFO, but there were some judgements by the honourable courts.
PFA one case law shared by Mr. H L Kumar (I down it from
Labour Law Reporter | A Practical Journal on Labour Laws & HR Management).
Hope this will fulfill your requirement/s.