I am unable to fulfill their request.

Sorry, but I am incapable of that request at present time. My capabilities are {limited to|restricted to a range of tasks. Perhaps someone else could try asking something else.

My purpose is to provide helpful and ethical assistance.

The term you/that/which used is associated with sexually explicit content, which website I am programmed to avoid.

Is there anything else any additional questions?

If so, please provide them and I'll do my best to assist with them within ethical and safe guidelines.