Hmmm... You are lucky!
After my problem remained unsolved for 5th night in row (CC again put my complaint status as "resolved" without actual fix), I also bought QP180 and set it to activate immediately by transferring all hours of earlier QP150 plan into the new account. But even this drastic measure didn't solve my problem. Despite QP180 plan being "upto 2mbps" I still got 512 kbps speeds. Called the CC again and they refused to accept low speed complaint and said that even QP180 is supposed to have guaranteed speed only upto 256 kbps and is officially supposed to vary between 256 kbps and 2mbps! I am thoroughly screwed. In my account, I now have pre-paid 330 hrs (150 + 180) with only 3 months validity and only 64KBps speed (whether its day or night). This is a nightmare!
My conclusion is that once the 2mbps speed gets reduced to 512kbps, its not technically possible for Tata to jack it to back to 2mbps irrespective of any plan/scheme.