Then, perhaps, you may have to send 70 more responses.
There are no guarantees of sales here on Fiverr. Just because you are a seller here, does not mean you are guaranteed to be instantly successful. Your success will take time. Realize too that you are competing with many other sellers for those very same Buyer Requests. Consider this: why should the buyer hire you, and not one of the 30+ other sellers competing for the job?
What are you doing to win the job? Or are you just sending cut and paste, “hire me, because I do good job” messages? Those kinds of messages are pointless, because you aren’t addressing the needs of the buyer, and you aren’t doing anything to appear better than your competition. Just because you send a random, “buy from me” response, does not mean you deserve a sale. Convince the buyer that YOU are the best choice for that job.
Pretend that every other seller is better than you, and that they will likely win the job. Then write a fantastic seller response that shows how you can be better than those winning sellers.
Don’t expect sales. EARN them.