Sears was out to do a yearly cleaning and now our dryer doesn't have heat. Easy fix or should I wait 3 weeks for them to come fix it?

They did not clean it properly and most likely you now have a blown safety. You have to take it totally apart and wash out all parts except the motor to get it clean. Sears will not do that. You also need to replace the belt and grease all bearings with white lithium grease. You will also need a good digital meter to find the safety that is bad. Here are some manuals: https://dl.dropboxusercontent.com/u/8010163/Whirlpool%20Dryers.zip
https://dl.dropboxusercontent.com/u/8010163/How%20to%20use%20Test%20Equipment%20Service%20Manu al.pdf
https://dl.dropboxusercontent.com/u/8010163/Whirlpool%2027%20inch%20Gas%20%26%20Electric%20Dry ers%20Service%20Manual.pdf