they were in thanksgiving for 10 days also i sent 7 support mail but there is no any return my side.
Have you tried the bitmain phone number?
here is the number +1-844-248-6246
Bitmain Warranty
3700 Quebec Street
Unit 100-239
Denver, Colorado 80207
USA
maybe if you have a relative or friend who lives where bitmain operates you could ask that relative or friend to go complain on your behalf
You can also try contacting them by this means
https://bitcointalk.org/index.php?topic=766448.0