Most likely you're going to need to purchase a new one... given that attempting to repair it will incur the cost of the replacement part (assuming you can even identify it and a supplier) plus the cost of the labour involved (unless you do it yourself... and you've already discovered how delicate these parts can be).
Honestly, at this point, given the cost of a Nano S, you're probably better off just buying a new device... unless you're something of an electronics repair tech

Basically what HCP said. Albeit you tried really hard not to do any permanent damage to the Ledger, you probably damaged it somewhere midway the process of checking it's integrity.
Whatever way you present to the seller, he would probably tell/or see that you tampered with it and no refund would be given. And considering the cost of it, the most efficient / quickest way to have it again is simply to buy another one.
My tip for you is to buy from Ledger itself, cut the middleman. This would allow you to have an increased amount of trust, since Ledger itself even says that they recommend not buying from third party sellers.
Considering the fact that some database of Ledger has been hacked (through their Shopify link), have you considered trezor.io? They claim to erase your information after the 90 days of return expire, but I believe you can request them to be deleted even before.