Doing a web search on your last name, it is apparently of Bantu origin (Bantu being a very large language family). There are a large number of Bantu languages spoken in the southern half of Africa, perhaps between 440 and 680 distinct Bantu languages, spoken by many distinct ethnic groups.
Whether or not the company you tested your DNA with can give a good ethnicity estimate depends on the number of people that have tested with it.
For example, a number of years ago my wife did her DNA test with Ancestry and they originally said she was 40-50% “Native American” which originally meant any indigenous ancestry in the Americas. We knew her ethnicity was Mexican, hence Mexican Indian. Over the years as more people tested this was refined, and currently identifies her ancestry coming from central Mexico, which we know to be correct because we have been able to document her ancestry back to people from Central Mexico identified in the records as “Indio.”
So if you DNA results are now presently very general, say “Southern Africa,” in the future, as more people are tested, this will be refined. In my wife’s case, her estimates were revised 3 or 4 times.
