Washington Mutual

My son has had a Washington Mutual credit card for about 18 months. He has a credit limit of $3250.00. His balance is approx. $2000.00. The problem is that he received a letter that they closed his account for 3 reasons. That he didn't pay more than his minimum payment, that he was at his credit limit, and also the took 6 months ratio and said he was a risk. None of these are true. He has always paid more than minimum on what he has, if they want $40.00 he pays $65.00-$80.00. He is not at his credit limit on anything and he has never been late with any bill, ever!!! He called them and said this makes no sense, they gave him the run a round so I got on the phone. I said if you want him to pay more than the minimum (even though he does then why not make the minimum higher? I said he is no where near his credit limit. I kept asking for the person I was speaking to for the next higher up. They kept tansferreing me until I got to the Executive Office level and they weren't there. They said they would call me back tomorrow. The 3 people I spoke to said nothing can be done, I want something done!!! He works hard and makes sure his bills are paid on time. He does not have alot of debt. He does have 4 charge cards, not with high balances, $300.00, $600.00, $1100.00 and this washington Mutal card. He has a fulltime job, works a 2nd job (not that he needs to) and lives at home. His FICO score was around 720 and I just checked it and is now at 674. Did this closing of the account make that score drop, (nothing else has changed) no credit purchases, and also why would and can Washington Mutual close his account? As soon as I mentioned a lawyer, they said since you threatened us with legal action you can talk to the Executive Dept. I explained that I will not stop, until this is resolved. Please give me any advice you can. Thank You