Poshmark should give you a refund on this your sweater is unwearable. I really admire those that have the skill to mend holes. DH and I tried to no avail to do a Sashiko repair on his sweater, but our inability to sew symmetrical stitches meant that it looked awful and after a number of attempts we gave up. We both started off with high hopes, only to realise that Sashiko stitching has to be immaculate to look intentional requiring skill beyond our beginner level. I hope you get a refund rather than having to attempt what is likely to be a tricky repair.