Von Bosh is right.....its usually the airport who supplies the service. However - they would expect to get some sort of advance notice of same, usually stated at time of booking and the airport is aware of same via the pax manifest. Hope that was done in your case....
Heard of the odd case of a pax arrive and didn't feel like walking to the gate and then ask for a wheelchair. At least the new legislation asks for min 36 hrs notice and therefore airports have the right to refuse these 'lazy' pax.