But i got this in an email from bitinstant
"Hey there,

This is to notify you that your order has been updated, please find the details below:


We have made a direct deposit into your MTGox account and there is no need to use the coupon system on this order"

Being a newbie, I may have screwed up my account number for transfer to Mt. Gox. Not asking anyone their number but would my merchant number which looks like "MX" work or does it have to be the number you see when you click Payment options>bitinstant on mt gox which is a 6 digit number or my account name?
I have a terrible fear I may have wasted $150 as i got an email saying the transfer was complete yet there are no funds in my account and support has not responded to my emails.

It is taking a while to process my order of $150 to mt. gox, which i wouldnt have an issue with if the price of bitcoins wasnt rising so fast. When I placed my order bitcoins were $63 market price and have gone up to nearly $73, so I have lost $20 and i'm sure other have lost much more. I plan on ordering something worth slightly less than 2 bitcoins so if this trend continues I will soon not have enough money in my account and will have to make another transaction for one order and ride this roller coaster all over again. Is there any system in place to remedy this? Perhaps having bitcoins transactions done at the price of the time of order?
It's a good service, but seems to be being poorly executed.