Did I act improperly?

In this game, the following occurred:
http://www.conquerclub.com/game.php?game=8714472
On 4-4-2011 at 12:35, I offered a 5 turn truce to Mr. Sour.
on 4-4-2011 at 17:38, Mr. Sour attacked me and took a region from me. (He took Astana, which would have prevented me from holding Asia.) He did not accept the truce in the game log.
On 4-5-2011 at 19:38, I moved again. I did not attack Mr. Sour, but assumed there was no truce
On 4-5-2011 at 12:35, Mr. Sour asked me to confirm the truce. (I did not see this message, and this was after he attacked me in Astana, and did not accept the truce offer.)
On 4-5-2011 at 18:25, Mr. Sour attacked me again in North America (Anchorage), and now held North America.
On 4-5-2011 at 21:41, I informed Mr. Sour there was no truce. (Put simply, the board had changed drastically. Because of his two attacks, he now held North America, and I couldn't hold Asia.)
On 4-10-2011 at 13:18, Mr. Sour claimed he was "sucker punched" and demanded "arbitration."
I have played this game for a while, and take truce offers seriously. My position: If Mr. Sour wanted a truce, he should have accepted it before he moved on 4-4-2011, and he should not have attacked me twice. I think his complaint 5 days later is revisionist history, and is proven false by the game log.
In order to clear my good name, I ask all of you: Did I act improperly?
http://www.conquerclub.com/game.php?game=8714472
On 4-4-2011 at 12:35, I offered a 5 turn truce to Mr. Sour.
on 4-4-2011 at 17:38, Mr. Sour attacked me and took a region from me. (He took Astana, which would have prevented me from holding Asia.) He did not accept the truce in the game log.
On 4-5-2011 at 19:38, I moved again. I did not attack Mr. Sour, but assumed there was no truce
On 4-5-2011 at 12:35, Mr. Sour asked me to confirm the truce. (I did not see this message, and this was after he attacked me in Astana, and did not accept the truce offer.)
On 4-5-2011 at 18:25, Mr. Sour attacked me again in North America (Anchorage), and now held North America.
On 4-5-2011 at 21:41, I informed Mr. Sour there was no truce. (Put simply, the board had changed drastically. Because of his two attacks, he now held North America, and I couldn't hold Asia.)
On 4-10-2011 at 13:18, Mr. Sour claimed he was "sucker punched" and demanded "arbitration."
I have played this game for a while, and take truce offers seriously. My position: If Mr. Sour wanted a truce, he should have accepted it before he moved on 4-4-2011, and he should not have attacked me twice. I think his complaint 5 days later is revisionist history, and is proven false by the game log.
In order to clear my good name, I ask all of you: Did I act improperly?