There is no "might" about it... Call the farrier...
If no follow-up call, then I would be calling my vet to come see the animal and find the cause, what ever it is ..
You can't, or shouldn't just leave the horse to be sore and not know why...if the animal is not walking normal in 2 more days time...get the vet out!
If the farrier can't be bothered returning your call, and returning to see the animal then to me the answer is clearly told and a new farrier it would be.
Oh...and once you secure the new farrier I would call this one, now fired
and let them know you realize they are busy and took their non-response as they no longer were wanting you as a client.
This is a courtesy call to let them know you understood their non-message returned and searched for another.
If, if they would like to discuss this they know how to reach you...otherwise, thank-you for their service.