I would like to believe even a free webhost makes enough from advertisements to support its client base with the same level of support that paid providers do, but let's face it; that's just not going to happen. If you are seeking unparallelled customer support options from a free webhost then you will most likely fall short every time. However, if you are awarded with free hosting from a paid web hosting provider then you should receive the same level of support as the paid clients unless you sign a free hosting tos that specifically dictates the terms of support that are offered to you as a free client.
Easy. Paid hosting clients pay money - the host can use these funds to hire support personnel. Free hosting users pay nothing - therefore, resources that can be devoted to them are very limited.