"Thank you for your message.
I have had to send the goods separately.
If they are not delivered within 10 days, please contact me.
I will launch an inquiry at the post office."
"Thank you for your message.
I have had to send the goods separately.
If they are not delivered within 10 days, please contact me.
I will launch an inquiry at the post office."
please note that I have used a formal tone. If you want to be informal: Grazie per il tuo messaggio.... ti prego di contattarmi.