Should the vendee be disturbed in the possession or ownership of the thing acquired, or should he have reasonable grounds to fear such disturbance, by a vindicatory action or a foreclosure of mortgage, he may suspend the payment of the price until the vendor has caused the disturbance or danger to cease, unless the latter gives security for the return of the price in a proper case, or it has been stipulated that, notwithstanding any such contingency, the vendee shall be bound to make the payment. A mere act of trespass shall not authorize the suspension of the payment of the price. (1502a)