I'm so sorry to hear about your phone, having one stolen is such a bad situation.
So you're saying that you bought a replacement back in February after the original device was stolen and didn't realize that you had insurance until now? I'm really really sorry but it's well outside of the buyers remorse period for the purchase of the device.
My guess (and please forgive my own assumption) is that the employees you had spoken with assumed that you were aware you had insurance but wanted to upgrade your device anyway, especially if you were aware that you had Apple-care with it (which can't be purchased as a stand-alone, only as an add-on to the insurance plans for Apple devices). It's the most likely explanation, though I'm sure it doesn't relieve your frustration and for that, I'm very sorry.
If anything could be done, I would reach out to T-Force via Twitter or Facebook and fill them in on the situation.