Voltage drops - what to do?

The voltage drops in the private sector, at night and closer to the morning, reaches 280 V, and in the evening up to 140-150 V, and even welders in the daytime. Believe me, this is horror. Welding apparently transformers. A year ago, the refrigerator burned out. The line is dead end. At the end of the street. Neighbors who do not understand the differences, and the Resovites simply stupidly include a fool. Despite the fact that after a call to the RES in about ten minutes, the welders stop cooking and the voltage is normal, and after they leave, too, after 15-20 minutes, everything is as before. On an official statement to the head of the RES, no action. Advise how to be. REACHED. Ukraine. Thanks in advance.