Whos' screw up?

A few weeks ago we decided that we needed to change banks. The one we had we were not happy with the service we were receiving. So we opened a new checking and savings account with another bank, closed out our old account and notified Social Security of the change of banks. We erroneously assumed (and you know the saying that goes with that word) that Sandy's check would be transferred with Mike's since he is her payee. Well that was not the case. Sandy's check went to the old savings account. Ok, lesson learned. We went to the old bank, took the money out and closed the savings account and vowed we would notify SS about the change to Sandy's account. Then our car died and we forgot to call SS. We did not remember until after Sandy's money did not show up. Mike called SS and they told us that they would electronically transfer the money and to give it 3-5 working days. We checked the bank account on-line and no money. Soooo Mike called SS again and they couldn't understand why the money wasn't there, but to give it another day and to call today if it wasn't there. Again, no money. Mike decided to give it another day. We get our mail today and we got notification from our old bank that they have reopened our old savings account and Sandy's money was deposited there. Now my question is this, what gave our old bank the right to open an account that has been closed and why didn't SS tell us when we were talking to them on the phone that Sandy's money had gone into the old account?