You just did it
.
Seriously..I've had 3 cable installs in 3 different locations over a lot of years with NTL and now VM and had to deal with NTL engineers a few times over that time due to faults or adding items on such as phones or TV and I've never had a bad experience. The same goes for customer services, in my experience they have never been less than very helpful and very courteous, through billing to cable modem support.
The India call centres however are a completely different matter. The total rubbish I've heard their 'techs' spout when trying to get a fix for friend or relative is unbelievable, it's totally pointless too since you have a problem you want fixing and all they do is delay that process and cost VM money. I don't know how much is saved having those call centres in India but I suspect it would even out when they take into account the amount of customer dissatisfaction and time wasted.