Impact Meter Services

We do not live in South Africa permanently. We visit South Africa for one or two months annually and stay at our house which is in a complex. The main switch of electricity is always switched off on our departure and our house is locked. A family member inspects the house from time to time and confirms the electricity always remains switched off. During our absence, the usage fluctuates from 5 to 58 monthly with an average of circa 22 units per month and an average cost of R33.46 monthly. During our occupancy of the house, our consumption of electricity for the period 07/06/2019 to 08/07/2019 was 754 units with a cost of R1, 294.14 and for the period 08/07/2019 to 07/08/2019 was 570 units with a cost of R946.84. We left South Africa at the end of July 2019 and have not returned since due to the restrictions of Covid19. Invoices dating back to 15/03/2017 started with a meter reading of 60473. Meter readings from 05/06/2019 to 06/05/2020 are from 62575 to 64112.
We received an invoice on 08/06/2020 with a meter reading of 64364 indicating a consumption of 252 units at a cost of R445.48 for the period 08/04/2020 to 08/05/2020
We also received an invoice on 03/07/2020 with a meter reading of 64975 depicting a consumption of 611 with a cost of R1, 154.42 for the period of 08/05/2020 to 08/06/2020, bearing in mind that nobody occupied the house during these periods and the main switch was switched off.
I phoned Impact meters from the UK and emailed them. I had a response from them with a photograph of the meter reading 30727 as proof of the electricity consumption. This reading does not correspond to any of the invoices received.
I have contacted them again by telephone and email on 16, 21 and 22 July but with no response.