No update on paid account

My electricity was cut off due to non payment. On the 22nd December 2015 I sent my sister to pay the account and open the electricity for us, she paid and I was able to buy the electricity same day. On that same day 22/12/15)they sent us a disconnection notice, I thought it was sent out of error never followed up on it, today 30/12/2015 I try to buy the electricity they say I'm disconnected, so which means I was only allowed to buy only on the day I paid...how does this happen?its hardly a month since I paid 2050 and opened the account.