At several years old, your camera is out of warranty.
The flickering might doubtfully be caused by some obscure setting, so if it worked previously, and if that setting is restored to what it was originally, the problem *might* be solved.
So I suggest - if you don't mind having all special settings and/or white balances, etc, erased from your camera - that you might want to try a factory settings reset.
On the Canon 7D, that is done by pressing
& scroll over to the tab with a wrench and three dots.
Clear all camera settings
then press SET
then choose OK
and press SET.
Camera's settings will all be cleared back to defaults.
If, after that, the flickering or jumping problem persists, then you have a problem in your camera's electronics controls, that most likely will need having it repair-serviced to cure.
To have your camera repair-serviced, go tohttp://www.canon.co.uk/Support/Consumer_Products/Repair_Information.aspx
for information on the repair process through Canon, &/or go tohttp://www.canon.co.uk/Support/Consumer_Products/Services_Locator/
and locate a repair center near you, for 'EOS' cameras (using the Select Filter function, select only that Canon device type).
If this answers your question adequately, please rate my Answer - hopefully, favorably - so that I may be paid for the work I have done on your quesiton. Thanks.