I second the approach of always having researched the alternatives. Particularly at small outstations, agents really just try to get you to your next connection and that is ORD.

All of the majors serve LON from ICT via ORD, DFW, IAH and ATL. Likely that AA would rebook you on one of those for the asking. Similarly, although you would have to get yourself to MCI, it's more than likely that AA would rebook you there as well.

Finally, if your flight is cancelled, you are always entitled to a full refund to your original form of payment. It may be the case that it is actually cheaper to purchase a new ticket on the routing you want (although this is something to check before acting).

Beyond finding alternatives, there really isn't much more to be done.