Same problem here. Ordered a phone through BoostUp and the order was cancelled without any notification and the payment was refunded. Hopefully this issue can get fixed soon!
I ordered the same phone a second time. Instead of checking out through PayPal, I used my card directly and my order shipped instead of being cancelled. Ordered last night and got notifications of the BoostUP being added to my bill the next day (about 12 hours after purchase). Boost Mobile could possibly be having a PayPal issue? Not 100% sure.
I hope this information helps you out if you are still looking to make a purchase.