Tried Wishnet. Been using it for two months. I mentioned my issues before taking their connection and they assured me that they will be done. The local cable operator was responsive,polite and helpful. He offered that he will install the connection and if the ports remain blocked he will not charge me anything. The Wishnet people came, now the engineer wasn't very smart and he kept talking on the phone and nothing needed to be done from my end, but eventually they opened the ports. Now for anyone interested you need to take a Biz plan for them to do this. So the ports were opened finally after about two days.
In 2 months of use I have had no down time, on occasion the box they supplied had to be restarted as the connection dropped. After restarting it worked. I asked the cable operator to replace the box with a new one and he did, after that no drops. Speed is dependent on source. If you connect to high speed servers it went upto 90% of download speed and upload was upto 50% sometimes earlier but these days it seems to be lower. In 2 months the total traffic per month (download and upload) averaged 29TB so that's fine. Happy with the service, no need to change.
Airtel is still there as backup.