USA benefits none given He stated he had tried to deliver to me a walmart card, I was not home, it was returned. none given, Other

I rec'd a phone call, unknown caller, unknown number today 5/1/11 at 1:55 pm. The male person did not give me his name, I had to ask who he represented he said usa benefits. He called me by my first name. He said that a Walmart gift card had been delivered to me, I was not at home, it was returned and he said it would be mailed out to me this week. I had already been charged for the $4.95 fee.
He proceeded to tell me what my debit card number was and the exp. date and told me to listen to a short message that would give me verification # to use the card. When it was over, he would be back to talk to me.
A woman came on the line, talking very fast, saying what he had said , and I would be charged 19.95 each month unless I called and canceled in 30 days. She proceeded to tell me about some other offer and if I didn't like it, I could cancel in 30 days and not be charged each. month $39.95. . She gave me 1 # 1-888-6822434, and then another offer, Member Services Dept. for 24.95. I could cancel in 30 days. -1-800-809-5986.
After each of the offers, she would ask if I would like to accept and I said no, yet she went on as if I had said nothing.The call stopped, I waited, and then dial tone!!!! A charge has already appeared on my Bank account today. Phone # 1-877-472-3388. I knew I had been scammed as soon as I hung up. But they had all my info.?????????How did they obtain it.  I am almost 77 yrs old and on fixed income.  I am calling my bank tomorrow and tell them my story. They will Help me, as they always have in the past, if I have any sucess, I will pass it on.......I am Furious..If that is all some people have to do.