Windows 10 Uefi Bootable Pendrive

i am currently in Salta, Argentina and will be travelling up to San Pedro De Atacama and then onto Uyuni and finally (eventually!) to La Paz in the next few weeks. My mum, bless her, wants to send me a package of Christmas tat and i have no idea where to tell her to send it. Does anyone know if there is a place in La Paz where you can send packages to from the UK so i can pick it up on the way through? I know that there are some South American Explorer Clubhouses dotted around SA which offer this service, but i dont think they have a clubhouse in Bolivia. Any ideas?