what is the reason behind your existing customer is using your product ? is it pricing or something else?
is your product equal or better than your competitor ? because when you close the price gap then customers will have one less factor to consider which is pricing between yours and their product.
then may be you can reasonably increase pricing if it's required, or may be do A/B testing.
But since you seem to be in the startup phase, if I were in your place (even though I don't know what your product is), I would focus on acquiring more lower-paying customers. You can always ask them to pay more at any time. Once my product has a reputation on par with my competitors and achieves feature parity with them, then I would think about increasing pricing.