You're absolutely right. "Give effect to" is correct. There's also the expression "take effect".
If your tutor and the lecturer in communications don't want to take my word for it either (I'm a native speaker and I teach Business English), then you could suggest they check the spelling by googling both "give effect" and "give affect" and then judge which is the better of the two based on the number of results you get from Google. They could also check one of the online dictionaries. For example: http://www.thefreedictionary.com/To+give+effect+to
Keep in mind, native speakers also make mistakes with these two words. In your case, apparently both your tutor and the lecturer in communications have made the same mistake that some native speakers make.
Good luck in your efforts to convince.
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