Relactation help

Hello! My baby couldn't latch so I mixed feed (80% breast milk and 20% formula) for about 1.5 months. I went back to work after that so I continued pumping for another 1 month at a lower frequency but fully formula fed as I couldn't figure out how to pump and feed at right timings. I've now stopped pumping for 3 weeks and was thinking of possibly re-lactating. Has anyone successfully re-lactated just with exclusive pumping and without any meds? Thank you in advance!