Can you please tell me if there is any difference in meaning between a customer called and a customer called in? For example:
Today one customer called and asked if we still had that tablet in stock.
Today one customer called in and asked if we still had that tablet in stock.
I've tried to find an answer on the internet, but I haven't been able to find an answer. I've heard both in the context, so I suppose both are perfectly natural, right? I'd like to know what the in adds to the meaning.