Diferença entre Present Perfect x Past Simple

Boa Tarde,
Fiquei com dúvidas em relação às frases abaixo.. Alguém poderia ajudar?


His father received so many complaints about the noise that he told Chris to sell his drums.
(Alguém sabe porquê não poderia ser usado o Present Perfect nessa frase? )

We have received over 50 letters of support in the last 10 days.
I have worked really hard this morning. Another two shelves to put up and then I think I'll have lunch.
(Ou porquê usar o Present perfect nessas, mesmo quando mencionado um tempo específico?)

Grata!