More often than not, ISP companies say you are on this speed while your speed is still the same. Upgrading a service provided by an ISP may take some time, but if this has taken more than a week of waiting, then I guess you are getting stiffed with an excuse.
For sure you can tell if the speed has changed via a speedtest site or upfront when you are downloading something on the net. But in most cases, some webservers can only give you a limited speed due to the fact that they run multiple servers on the same connection.
If your speed is still on the slower side as you thought, I'd suggest you call that guy again and ask him straightforward and let him show you "the real problem".