Source Code not linking contributions

We are trying to reverse some fraudulent donations  made via our website, in Tessitura. When trying to reverse the donation, we are unable to bring up the previous transaction as the source code it's linked to isn't giving us any line items. 

Any help you can offer would be fantastic as this is now very time sensitive.

For example:

We go to the contribution processing screen, search for my constituent, then enter my source code, in this case it is 2.  

We then select 'Adjust' which prompts an error message "There are no eligible contributions to adjust." Normally it would bring up a list of all transaction under that source code linked to the specific constituent. 

Any help would be greatly appreciated. 

Thank you!