Hi Murat
'Ne pas se lever' is the correct infinitive form for 'not getting up'.
e.g.
Je ne vais pas me lever tôt demain matin = I am not going to get up early tomorrow
Il ne va pas se lever avant elle car il a mal au dos = He is not going to get up before her as he has back ache
Ils ne se lèvent jamais avant 11 heures du matin = They never get out of bed before 11 am
Hope this helps!