I’d give a % discount coupon equal to the profit margin ($100 sale item costs you $40, give them a 60% off coupon for that item), free shipping.

You don’t lose any profit beyond shipping costs, they get a new item in the proper color for a good deal— seems like a win-win compromise.

If you really want to go for it— send the sister the same coupon for helping find the mistake. Send them each a few 10% off coupons to share with some friends. Now you have two happy, brand advocates!

As a customer, I’d be much less put off seeing someone reading a physical book or kindle instead of a mobile phone or tablet.

You need to focus on influencing positive outcomes instead of attempting to control using fear-based micromanaging. Set goals and require a daily activity summary. Provide bonuses to incentivize exceeding goals.

Focus on encouraging behavior you want instead of grinding your employee into a demoralized pile of nothing by attempting to punish behaviors that don’t affect anything.

If the employee hits the targets you set and they can provide a full summary of the daily activity, why are you bugging?

“I don’t work with customer-provided parts, but I’m happy to provide a price breakdown for your reference.”

When pressed about cheaper parts, respond with “when I buy parts and I break them, I assume that cost and provide new ones. When customers provide parts and I break them, I don’t replace them and I charge more for a return visit when new parts arrive. It’s much higher cost and slower repairs, so I eliminated that for a better experience and now I no longer use customer-provided parts.”