PLEASE please please read- I REALLY need your help! UPDATE UPDATE UPDATE

UPDATE AT BOTTOM

I have posted before about my gown but now theres more!
-went to try on gown, found mine, wanted to take pics they wouldn't let me (now they allow you to) They gave me 2 slips to try on, a medium a-line and a HUGE one. The HUGE was too HUGE so I was measured hem to hollow with a-line and 2 1/2' heels. Once I looked at pics I realized the dress looked droopy but it was too late I already ordered it.
-2 out of 3 measurements were an 8. I knew I was going to lose weight so I said order me the 8. (It has a corset so how bad could it be to order a little smaller) They refused and now my dress is HUGE on me. Once my 10 arrived they said 'you couldve signed off on the 8' I was pissed I was never given that option and my current measurements are a perfect 8.
-Once my dress arrived- all of a sudden they have this IN BETWEEN slip that is PERFECT but makes my dress too short to wear with heels but I order it anyway which they tell me is $60. It arrives last week and all of a sudden it is $125!!!!!!
-So now they tell me- no big deal we'll take it in and well let out some of the material on the pickups to make it longer. WHAT?

So now I have to spend a cap of $175 for alterations I shouldnt need if I was allowed to take a pic and sign off on my size. PLUS they are refusing to start my alterations until AUGUST and I am afraid because what if I am not happy with the outcome.. I will be left with no other options. SO should I say

'Either order me a new dres NOW or do the alterations NOW or I am taking my dress elsewhere?' Or should I leave the dress alone and wear flats and just let them take it in or am I being a BRIDEZILLA?????