Normally there is no direct contact between a Buyer and Seller. All communication goes through the Realtors in the transaction. This is done to prevent any information being misconstrued or deals made outside the contract. For example if the seller tells the buyer the Washer and Dryer convey with the sale, but those items are not made part of the sale with an Addendum. Then at the closing the Seller could say no those items don't convey and its a "he said she said" conundrum. This is one of the reasons it is always better to communicate through your agent, so there are records of the details of the sale. It's in your best interest to have your Realtor involved.
Normally a listing agent / company will not give you the contact information unless it is something personal or an emergancy between you and the seller. If it has anything to do with purchasing or leasing the property they will want all communication to be through them. That is if they have a normal listing contract with the seller.
Best of luck .. Bruce