In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
If the working at a call center facilitating stock exchange marketing and sales services involves executing unlawful transactions, then it is unlawful.
Answering your question, the General Iftaa’ Department in Jordan, states the following:
It is well known that bonds are usurious loans whereas shares are units of ownership in joint-stock companies.
The function of the “call center” is to execute clients’ orders regarding sales and purchases, so it could involve executing lawful as well as unlawful transactions.
Islam has forbidden whatever directly helps in committing sin since Allah the Almighty says, “Help you one another in righteousness and piety, but help you not one another in sin and rancor: fear Allah, for Allah is strict in punishment.” (Al-Ma`idah 5:2)
In fact, the execution of unlawful transactions is unlawful because it directly helps in committing sin.
Accordingly, if the job mentioned in the above question involves executing unlawful transactions, then it is unlawful to accept it.
But if it doesn’t involves executing unlawful transactions, then it is permissible to accept the job offer.
Almighty Allah knows best.