it might be considered "rebelism" against what you're being asked for
while they now made it accept that
the intension was to learn (a/the) present form(s) of "heten"
(if that's the proper main form for "heet")
while: yes, in English there might be "hoist" which is not that commonly used?
so to be actual, you have to paraphrase the verb for having a name, for not really being able to translate "heet" -directly- so why bother .. in this case .. especially
According to Google, both phrases seem to be used, but of course "Mijn naam is ..." corresponds to "My name is ..." quite literally, while "Ik heet ..." might be a bit closer to "I am called ..." (the English cognate to "heten" is now archaic, so there is no literal translation). But the meaning is more or less the same either way.
Because English and Dutch vowels don't sound the same. Over time, English has been influenced by Norman French, Medieval ecclesiastical Latin, Scots, and the other languages of the British Isles. It has also diverged from many of the other Germanic languages simply by virtue of being spoken on an island separated from its linguistic brethren. The other Germanic languages remained more tied to one another and their proto-germanic roots. It's no surprise that Dutch pronunciation is quite different than English. No languages sound much like English.
Not sure you can make an exact english equivalent. To tell someone your name in German or dutch you say ich heisse... or ik heet..., but in my experience in English more usually I am... To say my name is... is also not uncommon, though is that exactly like "ik heet"? To say "i am called..." to my ears at least sounds like what would be said if a lady named Margaret chose an alternative "I am called 'Peggy'" or "call me 'Peggy'".