Try a plunger: If it's a double sink, use a wet rag or rubber stopper to block the other drain. Place the plunger directly over the drain until it forms an air-tight seal. If you have trouble forming an air-tight seal with the plunger, run it under some hot water to make it more flexible. Move the plunger up and down to dislodge the clog from the drain.
Payment schedule: On a big job, especially a planned remodeling, the service provider may want the customer to pay 10 to 15 percent of the cost up front and 50 percent paid before the job is completed — especially if expensive materials need to be purchased for the project. Make sure you know what is expected. If you're suspicious, contact your state's professional licensing board or contracting board to ask about local standards. Many states set limits on what is allowed to be paid upfront.