I received an empty envelope and contacted the company through Amazon after work. I have already received their reply and it really seems like they are sincerely trying to correct the problem. Here the message I received:
Hi,
We are very sorry for the inconvenience. We shipped out quite a few of these and this is the second one with the same problem. We purchased low quality envelopes accidentally (they were advertised as heavy duty, like everything these days). We should have taped the envelopes to prevent this and we acknowledge that this is our fault. We are a very small business and are losing a lot of money over this, but I will take responsibility for it 100%. I will send you a replacement set of pliers in the morning, and would be happy to offer you a partial refund of the amount you think is fair. I hope for you to be at least marginally happy with your transaction in the end. Thank you for your business.
Mark
Sounds more than fair to me. I'll give them the best feedback I can when they come through and more business in the future when an opportunity presents itself.