Poor Servcie

We had the solar installed July last year. The Electricity usage has gone up even though there is no one at home. I have been querying this ever since the installation. I am fully aware that the price of electricity has gone up but this does not justify the usage and there is no one at home. Over 1000kw a month for an empty house? I was then told that the inverter is faulty and had to be replaced. I have to date not received any proof that the inverter in fact has been replaced and once again received a ridiculous account. Part of the agreement is to also wash the panels however this too has not been done so production is also affected. WORST DECISION EVER