If the Buyer has not turned in the Earnest Money per the contract then they are in default of the REPC. As a buyers agent you are required to notify the listing agent that the earnest money was not received on time as its a material fact concerning the client's ability to perform on the contract.
"An individual licensee shall uphold the following fiduciary duties in the course of representing a principal confidentiality, which prohibits the agent from disclosing, without permission, any information given to the agent by the principal that would likely weaken the principal's bargaining position if it were known, but excepting any known material fact concerning the client's ability to perform on the contract" R162-2f-401a(1)(d)(ii)
"If Buyer defaults, Seller may elect one of the following remedies: (a) cancel the REPC and retain the Earnest Money Deposit, or Deposits, if applicable, as liquidated damages; (b) maintain the Earnest Money Deposit, or Deposits, if applicable, in trust and sue Buyer to specifically enforce the REPC; or (c) return the Earnest Money Deposit, or Deposits, if applicable, to Buyer and pursue any other remedies available at law." (REPC 16.1)