So this happened when I was in the process of switching jobs. I got to the last round with 2 companies. Got an offer from one and negotiated a compensation package including a signing bonus, relocation expenses and an annual bonus in addition to the base salary.
I informed the second company that I have received an offer and need to respond in a few days so if they intend to make me an offer, they should. They got back to me with a much lower offer than company 1. I asked if this could be negotiated since I had a competing offer which was much better. They said they don't have the budget so I said no thanks. Within 15 mins I get another call from the HR of company 2 offering me slightly more than company 1 (verbal offer, not in writing). The catch is they want me to send them a copy of the offer I received from company 1. I had signed documents saying that I will not do this. So I told company 2 that I can't do this and they can send me the verbal offer in writing for me to consider it or I am accepting the other one. More bs from them on how they have been burned in the past when they sent written offer letters and candidates using it as a leverage to get better offers elsewhere and ditch them. I was like whatever, said no thank you. Accepted the other offer.
A few days later, I started getting contacted by the members of the hiring team from company 2 on LinkedIn and via email about how disappointed they were that I wasn't joining their company and if anything can be done. Sorry but it's too late!
The moral of the story is so not to get pressurized by companies. Know your worth and try to get paid what you should.