Well, you can and when once I was questioned by CC about making call from abroad, I told them my work requires traveling and my parents back home are old and not patient and competent enough to call CC and wait through the process and answer the technical questions. Therefore I have no option but to call on their behalf.
I further give them the registered mobile number, name, address and asked them what is their suggestion if they are in my shoes.
Not a single question was asked since and did the needful right away.
When I wanted to activate the infinty pack on my connection, the ladies did tell that is not possible this is not possible..
but it was cc guy who got it done in less than a minute.. I guess it depends on shift of the execs and ur luck and not on guys and gals who talk to u... :shy :shy