Best of luck with disputing the chargebacks. Make sure you make the job of the reviewer as easy as possible to ensure the fastest judgement.
Include all necessary evidence in your dispute, including screenshots of conversations with the customer, proof of delivery documentation, etc.
Laying out your case in the dispute is key for the reviewer to understand your side and make sure you win the chargeback.
After you’ve gotten out of this situation, like @bundler-marko mentioned the best way to prevent this from happening again is keeping your chargeback volume low.
I highly recommend setting up manual payment capture first - this gives you time to evaluate the customer and order before actually capturing the payment from their card. This step alone will signficantly cut your risk of chargebacks and reduce fees.
If you have a high volume of orders to process, you can still use Shopify Flow to automatically capture payments on low risk orders. Here’s a free workflow template you can use in Shopify Flow to do that.
Hope this helps.