I don't think the customer service will be much better if you speak Spanish - the CC agents are ill-trained and poorly paid (which of course applies to most CC agents). It's not their fault but they simply can't offer good customer service, whether they speak Spanish or English. My impression was that the English-speaking agents, who are probably based in Spain, were a bit more competent than the German-speaking ones who are probably students based in some obscure call-center somewhere in Germany.