Learn Italian: Non accetto più questa scusa! - I don't accept this excuse anymore!

In Italian, the phrase for "not anymore" is strictly non + [verb] + più. Unlike English, which usually puts "anymore" at the end of the thought, Italian requires più to sit immediately after the conjugated verb: non accetto più.

Can scusa be used to mean "apology" as well as "excuse"?

Yes! Depending on the context, scusa can mean either an "excuse" (like in this sentence) or an "apology". If you want to apologize, you can use the phrase chiedere scusa (literally: to ask for an apology).

Would it be correct to use the continuous tense non sto più accettando to mean "I am no longer accepting"?

While grammatically possible, it sounds very unnatural here. Italian typically uses the simple present (accetto) for mental states, opinions, and declarations. The continuous tense (stare + gerund) is heavily reserved for physical actions happening at the exact moment of speaking.

How would I use this sentence's vocabulary to say "I said that I wouldn't accept this excuse anymore" to practice the current lesson?

To express this "future in the past" in a reported clause, you would say: Ho detto che non avrei più accettato questa scusa. The main clause is in the past (ho detto), and the past conditional (avrei accettato) shows that your refusal was a future intention from that past perspective.