Jesus, the same thing used to threaten me twice, Xia Siyu threatened to trade this information for Bo Yan's "past," and Bo Yan was even more ruthless, outright making him buy Xiaoyu umbrellas!
The key is, if you're going to buy, you buy, but you really have to get several different brands! A sweep and you've got at least thirty, have you no shame!
Bo Yan had no choice, the stash of Xiaoyu umbrellas he had bought previously when he lived in the old house had all been used up. If Song Fengzhi were around, he could have asked Song Fengzhi to figure out a way to purchase them on his behalf. But now he's come alone and it's not convenient to order delivery nor to go buy them himself even with a mask on, so he could only have Han Yifan run the errand.
But Bo Yan had his ways to make him obediently comply, "Do you want to pursue her or not? If you help me, I'll help you too."