Always, always, always ask for second tier support when dealing with technical support. They will tell you no, but be insistent.

It sounds like you Eearthlink DSL connection is on the ragged edge of acceptable distance from the CO. Keep in mind that the distance in feet not only includes what the line owner (local phone co.) says the distance is from the CO to the building, but also the inside wiring. The length and quality of the inside wire plays a huge part in line quality.

If you consistently have problems you could ask Earthlink to drop your line speed which usually would increase reliability.