So, I have tried a number of sources to get conversions such as facebook sponsored ads, forum marketing etc. But still not enough conversions. Should I buy some traffic from fiverr? Will it be helpful? What's your say.
Buying traffic from fiverr is the worst option. Try Google Adwords they are pretty good in getting targeted traffic and conversions.
Have you tried consulting to a professional for what are the reasons you are not getting enough conversions? At first check out the most basic things such as landing pages, your targeted audience, their demographics, is your product is really worth having, what actually your audience need, your on-page factor along with mobile optimization etc.
Fiverr traffic is not good. Try something that can get you actual conversions. Maybe Google Adwords.