Business and Dealings

Changing one's dollars on the black market

Q: I am visiting Argentina for a month. I have come across that the Peso Dollar official rate and black market rate to be very different. The official rate is around 8 pesos while the black market rate is around 15 pesos. Is it permissible for me to change my dollars in the black market? Someone told me that it is not permissible because its a type of riba and cheating and going against the law of the country. Please advise.

Fittings and fixtures installed by the tenant

Q: If a person rents a house and during the time he occupied the premises,  he added fittings in the house that were not provided by the owner of the house (for example fitting burglar bars, lighting, etc,)

1. Can he demand the cost of the fittings from the owner at the time he leaves the place?

2. If the landlord refuses to give him the cost of the fittings he put into the house, can he remove the fittings when he leaves the house?