DeepSeek V4 Pro vs GPT-5.3-Codexfor writing emails

Subject: Update on your delivery timeline  

Dear [Customer Name],  

I’m writing to let you know that your order will arrive two weeks later than originally promised. We recently faced an unexpected failure in our supply chain, and as a result, we haven’t been able to meet the timeline we set together. This falls entirely on us, and I’m truly sorry.  

To make this right, I’ve applied a 15% discount to your order, which will be reflected in your final invoice. You don’t need to take any action—the adjustment is already in place.  

We’re worki…

**Subject:** Update on your order delivery

Hi [Customer Name],

I’m writing with an important update on order #[Order Number]. Your delivery is now expected to arrive about two weeks later than originally promised due to a failure in our supply chain that delayed a key component.

This delay is our responsibility, and I’m sorry for it.

To make this right, we will upgrade your shipment to express delivery at no extra cost as soon as it leaves our warehouse.

Your new estimated delivery date is [New Date]. I’ll continue to share updates until y…