Transmission Fluid - My car is ruined - help

[chattersking]

Toyota Yaris 2008 Auto with 60000 Kilometres. Toyota dealer asked $235 for transmission oil change. On craigslist found somebody willing to do it for $85. The guy drained and filled with about 3 litres of "CASTROL MULTI VEHICLE IMPORT ATF"
Now when Im reading on this site it says that I should only use "GENUINE TOYOTA ATF WS".
Eventhough my car seems to be running fine and didnt see any difference Im extremely worried that I may have used the wrong oil and ruined my transmission. When I called back the guy he says that oil is compatible with all toyota/honda other cars and should be no problem. I know that I should have gone to toyota dealership and get it done there but I was just trying to save some money :( had I known that I should have only used the Genuine toyota atf ws oil I would have never went to this guy.
Im extremely worried that I might have ruined my car and dont know what should i do, i cant even type properly because my hands are shaking. I have spent a lot of my hard earned money to buy this car and plan to keep it for a long time and dont want to damage it.

Please advise what should I do.