Sim Swap

I did an upgrade on-line at Autopage on the 18th of August. I did not realise that my new phone would require a nano sim card, so when my phone arrived, it had the wrong sim card with it. I went to Autopage on the 23rd of August to get my new nano sim and has been without a phone since then, as my sim card has still not been activated! Every time I phone the customer services line I get told to switch my phone off and to switch it on again in two hours, but up until now I am still not activated! How difficult can it be to activate a new sim card?