Transmission Fluid

Yesterday I had a friend drain my transmission fluid and put more in and replace the filter because there was shifting going on when my gears were changing. I drive a 2003 Subaru Legacy with an automatic transmission. The book said to put 9.8 quarts in, so we did. But we drained far less than that and today my check engine light is on and it smells like the fluid is burning and the shifting is still not fixed. Can you please help me with what I should do?