Is it permissible for a woman to work selling products over the phone?

Selling used gold as new

Working for a company that sells gold on credit

Writing a letter stating salary for someone who will use it to get a riba-based loan

Ruling on working in Bank al-Bilaad

Ruling on working as a security guard in an hotel

Ruling on working in a company that promotes satellite channels

Opening an internet café in which there is no supervision of users

Saving system in Aramco and attitude towards the various fatwas concerning it

Working in a riba-based bank without directly dealing with riba and depositing money in such a bank