Translate and keep the tone

Translate this text from [language, for example English] to [language, for example Spanish] so that it sounds natural to a native speaker, not like a translation.

What the text is: [email to a client / post / description of a service / terms of an agreement]
Who the reader is: [who they are, which country they're from, how formal communication usually is there]
Tone of the original: [for example: friendly but professional; slightly ironic]
What must not change: [brand and product names, numbers, deadlines, terms, people's names]

Do the following:
1. The full translation.
2. A table of places where you had to depart from a literal translation: "Original · Translation · Why."
3. Idioms, jokes and cultural references the reader might not understand, and how you handled them.
4. If the text addresses the reader directly (the informal or formal "you," first name or title and last name, and so on), suggest what's customary for the reader, for example tú or usted in Spanish.
5. A back-translation into [my language] to check that the meaning didn't change.

Rules: don't change numbers, dates, amounts or names. Don't add anything that isn't in the original. If a phrase is ambiguous, ask me.

[Text]