Had a similar situation, mobile provider had called me to offer me a deal, was no CLI showing - usual withheld affair, as is the case of many companies alas (th

Had a similar situation, mobile provider had called me to offer me a deal, was no CLI showing - usual withheld affair, as is the case of many companies alas (though mindful that can be spoofed). Again, same situation, wanted to very who I was and when I wanted them to verfy who they was we ended up in a circle-dance. But it is important and getting their number or in your case, a branch to go into - something you can prove with a degree of confidence is important. Many will happily give out information. In my early days of work(before CLI and still analogue exchanges afoot) a friend pulled a joke upon me, phoned up pretending to be TAX office and to verify details. It's easy to fall foul of such things and been a source of many scams against less aware and older people less savy of such. One way is to partialy give information and ask them for some back that they are verfying againt. Also if you ask them to verify details they will (legit even) use the data protection law flavour of the country to say they are not allowed to do that and very easy to get into a circle-dance. Which makes online more secure than the whole phone network with all it's legacy overhead opening up to abuse such as spoofing. Bit like the early days of the internet and spoofing IP's, not so easy today (mostly if routers configured right as most are).