Need a plumber now please July 24,2014

Help please! My sewer line has backed up I need a plumber willing to snake the drain but willing to accept a post dated check until July 31st. I have 2 sons, one just came home from the Army, I had to pay to get him home. The other just graduated from high school, has ADHD & Asperger's syndrome. I am a hard working person with a good job, but I unfortunately don't have the money for a plumber until the 31st when I get paid. There is sewage all over my patio and in the yard! Will someone one PLEASE help me? I signed up for sewage protection through the water company but it is not effective until August 16th. This happened before and they needed 1500 ft of snake to open the drain. Please call 412-628-...