Is it legal for my Kentucky energy company to charge me several large security deposits at once?

LG and E, my Louisville, KY energy company, recently charged me a bill of around $250.00 (for a tiny appartment) when my energy usage was only around $50. Every time I'm a few days late with a payment, they slap another security deposit on my account - I believe I am paying three security deposits simultanously. I read somewhere that in Kentucky law, any security deposit charged by an energy company can only be a small percentage of the average bill and can only be charged once. However I am not certain of my information. I tried complaining to the company and received no reply. (Wouldn't it be fun to put together a class action and sue the smokestacks right out from under this merciless Louisville Monopoly?)