What is the legal ruling on taking an amount of 5500 Saudi riyals from a company without its knowledge, with the intention of paying it back later, then using the amount to purchase necessities after leaving the job, knowing that the company denied my entitlements which exceed 20,0 Saudi riyals?

We understand from the question that you took an amount of money that was paid to you on behalf of the company and did not deliver it to the company. This is forbidden because it constitutes a breach of trust, and the amount remains your liability. However, if the client's obligation was discharged by paying you, and you have a confirmed right against the company that it denied, you may consider the amount that is your liability as part of your remaining right against the company. This falls under the category of "obtaining one's right," and it has been narrated from Al-Bukhari and Ibn Sirin that it is permissible for the wronged person to take retribution if they find the oppressor's money.