Yesterday WHAT was "on rent" for $700??? No idea what you're referring to, could be they found a tenant of sold whatever it is or it burned down or they killed the listing because they were tired if silly questions.
Without an address, I can't tell you why. The price of rent can fluctuate with the market. When a development has a small amount of occupied tenants, the rent goes down. When the development has a large number of occupied tenants, the rent goes up.