Inverter Muxstek

I am wrthing on behalf of Mrs R Roberst she bought an inverter from MB electrical in PortShepstone the inverter was installed in the place of an inverter that was damaged by lightning The new inverter only lasted 3days then it went into fault mode she took it back to MB electrical they send it away.The report that came back said it was overloaded.I installed the inverter the only thing that i change was i installed a surge arrestor to protecked the inverter. If it was damaged by overloading it would not last for three days it would have burnt in a 4hour loadshed not at the begining of a 2hour loadshedding I have send emails to Mustek and did not got any respons it is now a month that she is batteling with Mustek and MB electical she is 76 years old and does not know how to work a computer that is why i am helping her.If it is possible for hellopeter to assist her to get a response from Mustek or MB electrical