You haven't provided much information and that makes it very difficult to figure out what your problems might be.
A WhatsApp call may go unanswered for many reasons including you calling at a time when the person receiving your call is asleep because they are in a different time zone.
If you are getting your calls answered by someone in a different country then that might indicate that you are storing phone numbers for your contacts without a country code.
I always store phone numbers for my contacts in international format, even for contacts in my home country and this means that I can call one of my contacts correctly from anywhere in the world.
Here in Aotearoa New Zealand phone numbers within the same local region, on the same network do not need a prefix and so if my phone number is 912 4556 then someone else local and on the same network as me can key in that number, call and get me.
If they are outside the local area or on another network but within ANZ then they need to add a zero prefix (to indicate out of network) and then my local network id. In my case that would become 021 912 4556.
If they are outside of ANZ then they need a different prefix (not zero) to indicate an out of country call. This prefix can be either the plus sign (+) or double zero (00). Like most people I find the plus sign to be most convenient. Given that the ANZ country code is 64 someone outside of ANZ would then need to dial +64 21 912 4556 in order to call me.
Phone networks are relatively smart and so if I store my numbers in this format + xxx xxx 9999 9999 then they always work, even if I am in the same country, on the same network and within the same local region.
While WhatsApp doesn't use the international telephone network to make voice calls it does use the same logic to identify the correct recipient of your WhatsApp call.
Given that Spain's country code is 34, all my contacts in Spain have numbers starting with +34
If the number that you have been given starts with a zero then drop the starting zero. So if the number given is 0679 4438 2299 then it would become +34 679 4438 2299.
Lastly, WhatsApp can only initiate voice calls to a device that is running the WhatsApp computer program. In general, this means that you can only make WhatsApp calls to mobile phone numbers (rather than landline phone numbers). There are exceptions but for simplicity just figure that you can only phone smartphones and so they are all going to have a mobile phone number. In Spain, mobile phone numbers start with 6 or 7 (according to Wikipedia) and so all of my WhatsApp contacts in Spain have numbers that start with +34 6xx or +34 7xx
Where a business lists more than one phone number then use the number that starts with 6 or 7 when calling with WhatsApp.
Super lastly, most albergues are small businesses, many are family owned, and so, in general, people are not waiting around for you to phone them. They are usually busy doing other things and so, often, I find that the most reliable way of contacting an albergue is to send a WhatsApp message first so that the recipient can reply when it is convenient for them. Then, if necessary, I can phone them on WhatsApp and have a voice conversation. Remembering that you are calling someone in Spain and so they are probably going to answer in Spanish and may or may not understand and speak English.
Edited to acknowledge that mobile numbers in Spain can start with either 6 or 7.
When I read further down in the Wikipedia entry I saw that she is correct and mobile phone numbers in Spain can start with either 6 or 7.
