Tata Sky — No signal due to system upgrade

Address:

Mumbai City, Maharashtra

Well I lost my signal on 11 of april, the reason given was system upgrade.Past one week I am complaining about it to customer care but my call is either sentenced to be on hold or they tell me that they will call in 8 hours. But till today's time they didn't call me back.They just take complaint of mine and forget it without taking an action against it. What else can I do to get justice...