Spokesman Sello Hatang said the notice that R6468.48 was outstanding had been delivered to the wrong address.
A copy of the pre-termination notice was posted on Eyewitness News’s website.
Dated August 1, the notice advises that the amount has been outstanding for more than 30 days and warns that if it is not paid, or an arrangement is not made to pay it, a “discontinuation or restriction of services” will follow, as well as possible legal action.
But, Hatang said he believed the notice had been stuck on the wrong house.
“Apparently the address is wrong,” Hatang said.
“I don’t understand where the story is because it is the wrong address; it says Oaklands.”
The address on the notice is 49 Fourth Street, Oaklands.
According to a map of Johannesburg, Mandela’s house seems to be on the border between Oaklands and Houghton Estate.
The City of Johannesburg could not immediately be reached for comment.
Mandela is spending his 59th day at the Medi-Clinic Heart Hospital in Pretoria after being admitted on June 8 with a recurring lung infection.
The presidency said his condition was still critical but stable.