Inverter Not Working on Second Use

The inverter sold is 800 W, the input rating is only 25 which leads me to believe this is actually more like a 300 W inverter, on the website they said you can use a car battery - which I did at 45 A rating - which is the probable cause of the damage. The \technical"guy laughed me off and said I can only use a deep cycle - why is the website full misinformation. At China Mall I looked at a 800 W inverter with 67 A rating which is more like 800 W. To get P (W) = Amps x Volts. I left a negative rating on the reviews section and it got removed - I am of the opinion that they only keep 5 and 4 star ratings and drop the lower ratings from their website. All attempts to have this issue resolved failed. At lease here my negative rating will not be removed."""