u/Exosan

My garage door lifts just fine and sits pretty close to level when it's closed. The problem is, when it is open and I want to close it, it descends unevenly. The right side sags quite a bit compared to the left. I imagine it's due to uneven tension on the cables or springs. Occasionally this causes the whole door to malfunction, abort closing, and return to open position.

I'd like to get it taken care of before it stops working altogether. Normally I'm all for DIY home projects, but I don't want to touch garage door springs with a 10 foot pole. That's a job for a licensed, insured professional.

Who can I trust to fix this properly at a fair price?

Thanks.