They will get used to you sooner or later, they usually get used to there new home quicker than a month tho. Are they in a room where people dont come into much? If so try to go into the room more even if its just to go in sit down for a few mins then leave
As already said you tank is too small for 1 full size oscar. Oscars get massive about a foot long and they get thick and deep too. Now imagine 2 like that in your tank. Oscars also grow quick so try to sort out a bigger tank asap. 75g is the minimum for 2 oscars. Even with a 75g you will need to do big water changes every week, probably 40 or 50%. Test your water weekly, ammonia and nitrite should be zero, nitrate ideally below 20 but below 40 will do, if its above 40 then a large water change is needed
