Translation:If you had not had the books, you would not have read
after so many forced translations of "had not," this one only accepts "did not."
Hmm, but if it's in the hypothetical past rather than the hypothetical present, it should be "had not".
The distinction is apparently not maintained as strictly in Swahili as it is in English, but, more or less:
Msingalikuwa na = If you had not had
Msingekuwa na = If you did not have
Either the dictionary hints are wrong, or the suggested translation is wrong. A new mistake to add to the many.