Careful with the phone call, because any promises or deals made on the phone can turn into a he-said/she-said sort of fiasco. If you do try to speak with him and get some solution worked out over the phone, immediately send an e-mail or other written communication that "thanks" him for the phone call and repeats, in detail, exactly what was agreed upon on the phone. While the "good feelings" from the phone call are still being felt (or pretended), they are likely to respond and acknowledge the deal. But even if they don't, the lack of argument ("What phone call?" or "Wait, that wasn't our deal...") can be looked at as an acknowledgement of the agreement.
Good luck.