Refund Problem

Last year I filed my taxes through Turbo Tax and designated I would like my refund deposited. Afterward, I received a letter by mail saying that my refund amount was changed due to an error in my reporting. That letter was thrown away, so I do not know my refund amount.  How can I find out about my refund status without this exact number?  Or how can I find that exact number if my tax paperwork does not have that new number since the IRS adjusted it on their end?  I appreciate your help.