I would not recommend you to buy these links from services here, but you can make a few posts yourself as you understand your niche best on relevant only forums and topics, sometimes good forum link can bring you referral traffic for long time. And you don't want to make any spammy links even if they maybe temporarily work with your competition. You could cry when another Google update happen and there are few every year. Continue doing your work and try making brand and your domain stronger. Do outreach and try to get as many you can good quality and relevant links. I also lost traffic with recent update 60-70% but think like this. Same way you outranked competition in past, now its the time to drop but it doesn't mean you will stay down forever, sites go up and down all the time nobody keep #1 forever.