Non-native English speaker here. I don't know what the proper phonetical representation is for my pronunciation, but it sounds like 'kept', just with a b and a softer p.
Like Johnny Dept. hahah
Imagine skipping i in debit. Or just say deb - it will be close. I always pronounced it somewhat like this. [1] The worst thing is that i had heard the word pronounced by native speakers hundreds of times and did not notice. Now i am not even sure that b is there in [1]. Here is another example that certainly has b[2].