I received a text from an unknown number just before noon asking me if my full name was my full name, which seems a little...not great for security. I'd rather they just emailed me at my shared email address for professional interactions. The text shared who the person messaging me was and their company, stated I was selected for an interview for a summer internship on Saturday next week, asked if I was still interested, but told me they only had one time slot left. When I didn't respond for 4 hours due to working, I received a message saying, "Texting one more time before removing you from consideration. Please respond." The whole interaction was incredibly unprofessional. Expecting a response during business hours from someone in under 4 hours is unreasonable. Offering interviews to someone with a single time slot left is also unprofessional. It felt very much like they didn't value the time and lives of their potential employees. I replied back I'd already accepted another offer, thanked her for the opportunity, and wished her the best. She replied back "ok thanks".