SINGLE START AND DOUBLE START NUT

Hi, I am newbie

I've got problem with my ball screw and nut set I bought from a supplier, I cannot install nut into ball screw, it stuck in the first lap then balls drop.
The screw is 20mm diameter, 10mm lead double start, but the nut has only 1 groove with 1 return, is it single start nut?
Is there any case a single start nut can match a double start ball screw?

Sorry I am not good at English, thank you very much :)

I think a 20mm lead single start could work with a 10mm lead double start, but could only transmit half the force (one of the starts wouldn't be used.)