Being Nickel and Dimed by Airline Vacation Customer Service?

I booked through the website of an airline vacation site, 2 months ago.

I recently had to make a change (extension) to the booking. So I called their support number.

I feel like they were providing much more than customer service/support, but sort of trying to nickel and dime me; which is fine. But, I'm new to this and just want to get a better sense of it all; is my intuition right, if you will.

Thus, my post here. Have you had similar experiences and can you share your thoughts?

My apologies for the long post. Just really need some advice/help. Thanks in advance.

Issue #1
I pay $50 to make a change ... if I'm outside the "within 40 days of travel".
I pay $200 ... if I'm inside that window.

I count from the start date of travel, backwards.
I feel like I have 2 days before the "within 40 days of travel" kick in.

1st day I call them:
The rep says I have today and tomorrow, to make a change and be charged the $50.
I call again later. Another rep says nope too late, $200 to make a change today.

2nd day I call them:
Yet another rep says yesterday was my last day to be charged $50. Today, $200 to make change.

Doesn't make sense does it??

So we get past issue #1, which by the way I was on hold for about 3 hours, while they sorted out their data and records for the rebooking. It didn't make sense to me that it took that long. But I'm cool with it. It's sorted out.

Issue #2
I'm charged the $50 penalty and $400 to extend the booking. So I have to pay $450 extra. I agree to pay that.

When I get the confirmation email for the rebooking, a $60 item is missing that was in the original booking. Nothing was mentioned about taking that off. Just that I would pay the penalty and the extra money for the extended booking.

I call them up. I say the $60 item that was in the original booking is now missing. They say I have to pay $60 to get that ... they forgot to include it. WTF?

I already paid for that in the original booking, and now I have to pay it again?

The explanation was that I was misquoted the cost for the rebooking. So instead of $450 I should have been told $510 ($450 + the $60 item).

In my mind, I feel like they already charged me $510, since they took out the $60 item and I no longer have that to use.

I still feel like I'm being double-dipped. So I ask for the supervisor and they agree to include it. But, then I never get a confirmation email that they made the change. DAMN IT! I have to call them again.

Is this typical behaviour? I thought they were more customer service/support then sales. But it seems like they ARE sales.