Yes they have confirmed it's locked.
Usually, I don't buy MiFi. Somehow these devices usually have a weak network reception. So I mostly recycle old phones to work as a router. At present, none of the recycled phones has 4G. Also, all of the 4G MiFi routers that are currently been sold by service providers are locked. Checked two on jumia that are unclocked and I think the price is just a knock-off. But still, MiFi haven't worked well with me. Had one from Safaricom and sold it due to weak network reception. Got another from Orange. Same thing happened.
So I'm looking into purchasing a cheap 4G phone that I can use as a router at home. So far I think the Samsung Z2 fits this criteria but it's a Tizen phone. Hope I can get an Android one. Could have gone to OLX but simu za kuiba is no go zone for me. Only if I get someone with the original box of the phone that is when I might consider the buying from OLX. Still looking for one though.