I had no less than six calls from Indian call centres claiming to be "BT Openreach Technical Dept" yesterday, all wangting to warn me about viruses on my internet connection. Each had a different calling line ID, one even claiming to be local - same UK area code as myself. In each case I was able to annoy them enough to get them to swear at me, always cheers me up.
But in the middle of it all, I got another call from an Indian call centre. As usual, there was a second or two's pause, while the predictive caller was connected to an available 'sucker'. This time again, it was "BT Openreach", but wanting to talk to me about my phone line, as opposed to my internet connection. And that one was genuine, I'd had a phone fault for several days that was cleared yesterday morning, they were calling to make sure I was happy for them to close the fault. Thankfully I immediately twigged it was genuine, and was nice to them.
The point is though, as long as BT persist in using Indian call centres, and expect their customers to take Indian call centres seriously, they can't really be surprised when their customers fall for scams from Indian call centres.