pavillion desktop internal power port short

My HP Pavillion notebook AC power port has a loose connection... not the pin, but the solder weld attaching the port to the motherboard. I sent in for repair (they said no charge as it was a "notification" problem). It came back with paperwork stating the problem was duplicated and motherboard was replaced. It still shorts out and switches from AC to battery, especially when i have to move the notebook (even a little) but also shorts out and switches to battery even when i'm not even touching it. follow up calls required me to go buy a new adapter ($80), which didn't make any difference. Last call i was told it would cost $400 to fix and the previous repair was NOT done as it was not under warranty. Why did one rep tell me to ship it, it was free, and paperwork indicated motherboard was replaced; and NOW i'm told it's not free and the motherboard never was replaced as indicated? then they suggested i go buy a new computer! i just purchased this product 16 months ago and would expect better lifespan than that! i'm getting the big run-around! I believe this is a basic design flaw. Even when the laptop is just sitting on my desk, the AC adapter sort of "hangs" in the air out the side of the computer and must be continually putting stress on the power port weld on the motherboard. i have taken care to support the cord when moving the laptop, but it still seems like a better design is indicated to prevent shorting out the connection. I currently have a pack of post-it notes supporting the weight of the AC adapter so it doesn't pull down on the port, which helps, but it still shorts out peirodically. HELP!