Were you a member of Cashbaq.com? Unfortunately they didn't make it through the recession and went out of business. You probably kisssed good-bye any rebates you were owed. Maybe you even wrote off all rebate sites. I hope not because I can tell you that with the exception of Cashbaq.com, which I had received checks from in the past, I have had no problems getting money from Ebates and Mr. Rebates.
There is some good news about Cashbaq. Ebates is offering former Cashbaq members the rebates they earned but were unable to collect. If you are a current member of Ebates check your e-mail for details. It says they will give you the amount of your Cashbaq balance for returning to Ebates. I never left Ebates but was still able to take advantage of the offer. If you are not an Ebates member you may still be able to sign up and get your rebate so give it a try.