Niubility B14 - is not possible to drive at a speed of 10 km/h

NIUBILITY B14 - When pedaling with engine assistance, it is not possible to drive at a speed lower than 15kph.
For example, it is not possible to drive at a speed of 10 km/h.
When pedaling slowly, the bike accelerates sharply to 15km/h.
When starting by pedaling, the bike will accelerate sharply to 15km/h.
Only from a speed of 15km/h can the speed of the e-bike be regulated by the pedaling intensity.