Can anyone help me walk through making tags for my site?

As many of you know, I own a digital marketing agency. There's a client we have who is a financial company, whose website we rebuild from scratch. For the past year, we built lead generation systems and funnel for them with our own software subscription and tools, including Google ads under our MCC account, online forms with our formstack account, zapiers and automation, online calendars and so forth. At the beginning of January, they told me that they want to cut back our services to only social media and email marketing… Cutting all the Ad management. They told me they are cutting back their budget. When I pointed out that I do have a cancellation fee clause in my contract they refused to pay the cancellation fee. Now this client is basically firing us… Did not want to pay any kind of 30 day cancellation fee as per our contract. We continue to do their social media and email Marketing at the reduced rate.Then a few weeks later, they asked if we could speak with their "AI consultant" and also asked whether we would be able to migrate the account to be managed by someone else. I don't hold any client accounts hostage so I said yes I can, but you will have to pay a fee equivalent to one month of services for us to help with any tech support and transition. This consultant set up a meeting with my staff member and started asking her all kinds of questions and for logins into all our software systems and how we set up all the funnels and infrastructure and ad strategy. He followed up with a long list of systems he wants access to. I told him that if he wants our support with this, he will have to pay the estimate I sent, which covers all the tech support that he is asking for. This then led to the clients completely cancelling all our services and calling me freaking out because we own all the platforms that we built their whole lead acquisition system on yes it's our tech stack!) They are saying that we should've set up everything and let them own all the software accounts to run all of this. This was never agreed upon. They are freaking out on me because I also sent them an estimate for a $4000 transition fee to migrate all their data and consult with them on how to rebuild the system on their own accounts if that's what they want.