What payment systems do they use?

https://nsfx.com/    

NSFX is authorized and regulated by the Malta Financial Services Authority (MFSA) as a MiFID firm and holds a Category 3 Investment Services License (License No. IS/56519). 

As for the question you asked, we recommend that you ask the official customer services directly for a more accurate answer. Fore more details on this broker you can check our full NSFX review.