The bank which needs to approve the sale is NOT the seller. They are not a party to the contract. Under normal circumstances the contract is RATIFIED when the Seller signs it. Just like a contract is ratified but contingent on a Home Inspection, the contract is Ratified but contingent on 3rd party approval. This subject is truly an issue with many agents who do not understand the 3rd party approval CONTINGENCY.
In my area, Northern Virginia, many companies have started using a Short Sale Addendum, developed by the companies, not by our Board of Realtors, which includes verbage indicating that parties agree it is not ratifed until the Seller delivers to the Buyer proof of the 3rd party approval. The addendum also says that the Earnest Money Deposit is not to be deposited until 3rd party approval is received. How can the check be deposited if the contract is not ratified.
If your contract has this type of addendum, spelling out that it is not ratified until the 3rd party approval then the agent is correct not to change the status in the MLS. If though there is no addendum spelling this out, and the contract is Ratified (look on your contract for a ratification date), and your check was deposited, then the status should be changed and you agent should be making calls insisting the listing agent change the status. With my MLS if you do not change the status an agent can be fined as much as $100 for the first violation, and if they continue to leave it Active the fine will rise.
You should push the issue with your agent to get the listing agent to change the status, and if they do not get results go to their manager and have them make a call.
Best of luck