.... RENFE's site is a piece of c**p, and the management of the company is, at its best, a bunch of incompetents with no sense of market competition much less customer service. That summarizes all.
One needs to understand this company was instaurated in 1941 as a de-facto monopoly by the fascist regime of dictator Franco with the nationalisation of existing Spain's railway companies after he won the war in 1939. The company, much like other former national monopolies under a dictatorship -ie utilities- was plagued with nepotism and corruption and bribes. Unfortunately, the company's culture continues to be one of arrogance, disdain for customers and lack of understanding of market "rules", despite new generations of management and many marketing campaigns to overturn their poor image. The company had to split into two, one handling the trains (RENFE) and another one handling the infrastructure (ADIF) in 2005 in order to adhere to the anti-monopoly directives of the EU -Spain joined the EU in 1986. But scandals have continued to surface in both companies, like this one of management unsanctioned pluses in 2017 or this other one uncovered this year in which the construction of the high-speed train between the cities of Mecca and Medina in Saudi Arabia is suspected to have been riddled with bribes, over-costs and illegal commissions, even the Spanish former King is thought to be involved.
A bit of background is always fundamental to understand why RENFE is like it is.