Registration Woes and Frustrating Customer Service

Will be moving into a new house soon, so I went ahead and ordered FIOS service. After getting the order confirmation, I go to register for MyVerizon, where I'm told the following:

Would you like to use an Existing Verizon Wireless User ID?
If you have an existing Verizon Wireless account, you can use your existing User ID or Mobile Number to manage Residential and Wireless Services online. We may also use contact information from either account to send you important account related notices.
Great! Having one login instead of two sounds like a good idea. Try to login using my wireless ID when I'm prompted, and I'm told it's already taken/invalid. Strange. I finally figure out that it's probably because I had FIOS a few years ago with that same login. So I wind up talking to customer service a bunch of different times:
  1. Call the registration help number. I'm told it's a customer service issue. Transferred.
  2. Talk to customer service, told it has to be escalated to a specialist. Transferred.
  3. After transfer, I'm told a manager can deactivate or change the old account so I can then use it again to keep wireless/residential together. Great! I'm put on hold for an hour and figure I was forgotten about, so I hang up and try customer service again.
  4. This time, the customer service rep, after loudly yawning into the phone a number of times and acting completely disinterested, tells me it's a registration help issue, and tries to transfer me back to the people I originally talk to in 1 above. She hangs up on me instead.
  5. I call back the the registration help line anyway, and am told that I can't use the wireless login ID at all, contradicting what I was told in 3 and what their very website says during registration. I decide to thank her for her time and try again to get someone else.
  6. This time I try chat. I'm told, just like in 5, that I can't use the wireless ID. When I point out the "would you like to use an existing Verizon Wireless User ID" bit from above, she then corrects herself by saying I can use the ID, but not the password. What?

At this point I gave up completely and just registered using a different username, lacking any confidence whatsoever in finding someone who knows what they're talking about (except for the guy in 3, he knew, but forgot about me).

Re: Registration Woes and Frustrating Customer Service
Specialist - Level 1

Just want to make sure you are on the correct page. You should have started on Do not use the register at the top of verizon page. If you cannot enter the credentials there and get in, skip that section. Getting help will be impossible. FIOS rep cant see or verify your Wireless creds. Once service is installed you will not be able to get onto internet until you complete the terms of service which is on the same page. You may want to create a new user name. You may be able to get back your old Verizon user name, but the name on both accounts must be the same and you need the account number from old service.