Worst product and service

I bought a UPS from Waterfall Incredible in November 2023 to assist with my PC during load shedding, being assured it would last between 2 and 4 hours, the product failed miserably up to my expectations and was only lasting half and hour. I took it in on 7th of February 2024, to be advised no swap out only replace and repair in 21 days .I think this a poor show that no offer to replace while i wait or even communicate with the client. This tantamount to theft in my opinion. They have no expected date of the items being returned or nay knowledge what so ever when i may have the item returned. I demand compensation or money back