Can I stop by Electric service from being shut off?

I am 3 months behind on my Con Edison (electric) bill and I have by end of business today to Pay $96.00 However, if I don't pay that by today then I will have to $455 + a $120 security deposit. Problem is (though I haven't paid in 3 months due to loss of job) it's only 3 months and I usually only pay about $40 bux a month. I have no idea why I'd owe $455!! Help!