The principal is not liable for the expenses incurred by the agent in the following cases:
(1) If the agent acted in contravention of the principal's instructions, unless the latter should wish to avail himself of the benefits derived from the contract;
(2) When the expenses were due to the fault of the agent;
(3) When the agent incurred them with knowledge that an unfavorable result would ensue, if the principal was not aware thereof;
(4) When it was stipulated that the expenses would be borne by the agent, or that the latter would be allowed only a certain sum. (n)