In Spain it is an obligation of the law that all documents , invoices , instruction manual and any texts about the products on the market are published in Spanish
The majority of salespersons only have relationship with people of their own country.
This suggests that the requirement to speak English , is simply a filter in recruitment, unless you wish to work in a multinational or global company, where it is necessary to have a common language . This point indicates that for any improvement in employment, it is necessary to have a knowledge of the English language.
Perhaps, my friend, there are two details that did not think of them : The information, today , Internet is so fast , and information internet have 80% of the content are in English, in addition , information is always better the original language and not in translations .
You must learn English