Substantially Increased MOQ

I am an experienced entrepreneur looking to expand my business revenue streams by adding e-commerce retail in my industry. I found a supplier and product I liked via alibaba, and asked for a video call to ask some questions as the chat with time zones was taking too long over many days for me. It’s my first time sourcing product as I own a service based business. I talked about my quite aggressive marketing and distribution plan as I want to make sure they will be able to produce as sales increase. During the call, my contact increased the MOQ substantially, from like 840 bags to 15,000 bags and asked if paying for that MOQ under 30/70 terms would be achievable. I was shocked; I had to look back on our messages from earlier to double check I wasn’t wrong. I told her I need to crunch numbers and discuss with my team because it seemed to me like she was attempting to dissuade me from buying from them. I’m wondering if I did something wrong or if I’m reading this right? Is that normal for manufacturers to pull that kind of thing before the initial order has been made?