Pathetic, horrible service, once again

It seems as though I need to come on a platform to get help. My meter box is blocked for the third time and I am so so frustrated. I don't understand how if it's prepaid, I'm so upset. Bianca said my box was unblocked but now I can't buy again and they say I'm in a minus again. How can my account be in a minus if I can't buy electricity without paying for it. Please please can someone help me, this service is horrible and pathetic.