It sounds fine to my American ears although I would probably use the present perfect in the sentence prior as well:
"Lindsay's not answering. Maybe she has left her phone at home." (or she's left.)
"Well, she's called me today, so I don't think that's the case."
But I'd like to state that it is common for people to say it in the simple past as an informal way to say it; however, if one were writing a paper, it would probably not be written without being in the present perfect. The reason for this is that many natives of any language like shortcuts; we don't want to say all of those words if we can convey the information in a simpler form.
Despite the past tense being simpler in common parlance, most people would ask the statements above in a question form this way:
"Has she called you today?"
"Has she left her phone at home?"
The second example above may be commonly heard in the past simple (whereas the first one would probably not be heard as such), but, in that case, the speaker is usually omitting a clause that he deems implicit to the listener:
"Did she leave her phone at home (when she left for work today)?"
The above construction, however, does not suggest how many times she has called you. If you want to convey the meaning that she has called you a few times and may call again, I would write it and say it this way:
"Has she been calling you all day?"
"She has been calling me all day today." (or just all day)