Carrier Ac - AC automatically tripping

AC was automatically tripping and was getting off. Authorized Carrier AC service person visited in Nov ****. Totally * teams visited. They suggested that, because of the dust only issue is happening and he suggested jet wash for the AC. After the JET wash was done, AC was working fine. Totally we had paid around ****. Since it's winter season did not use the AC much. Now, during March when we started using the AC regularly it again started the same issue. Now the technician is saying that we need to check the electrical line and also put a double booster stabilizer which might be the main cause of the issue. No other carrier technician suggested the same earlier. And he did not even open the AC and he did not even spent * minutes only checking the AC. But he said he will charge Rs. *** even though the AC is not in working condition now. Only after putting stabilizer we can confirm whether its working normally or not.