Pronovias dress brides

I bought my dress at Pronovias in NYC at their flagship store and since I'm having the dress altered from v-neck strap to sweetheart strapless I decided to have the designer do the alterations which comes to $700
but i just read online that the alterations department at Pronovias got some negative reviews from brides so now I'm nervous. Anyone get alterations done there??? Should I get them done there or somewhere else??
TIA!!