diff --git a/app/services/files/create_service.rb b/app/services/files/create_service.rb
index 185ab26..1876dba 100644
--- a/app/services/files/create_service.rb
+++ b/app/services/files/create_service.rb
@@ -24,7 +24,8 @@ module Files
         return error("Your changes could not be committed, because file name contains not allowed characters")
       end
 
-      blob = repository.blob_at(ref, file_path)
+      commit = repository.commit(ref)
+      blob = repository.blob_at(commit.sha, file_path)
 
       if blob
         return error("Your changes could not be committed, because file with such name exists")
diff --git a/app/services/files/delete_service.rb b/app/services/files/delete_service.rb
index 30e512d..bacd0cc 100644
--- a/app/services/files/delete_service.rb
+++ b/app/services/files/delete_service.rb
@@ -17,7 +17,8 @@ module Files
         return error("You can only create files if you are on top of a branch")
       end
 
-      blob = repository.blob_at(ref, path)
+      commit = repository.commit(ref)
+      blob = repository.blob_at(commit.sha, path)
 
       unless blob
         return error("You can only edit text files")
diff --git a/app/services/files/update_service.rb b/app/services/files/update_service.rb
index d59802a..19bd62e 100644
--- a/app/services/files/update_service.rb
+++ b/app/services/files/update_service.rb
@@ -17,7 +17,8 @@ module Files
         return error("You can only create files if you are on top of a branch")
       end
 
-      blob = repository.blob_at(ref, path)
+      commit = repository.commit(ref)
+      blob = repository.blob_at(commit.sha, path)
 
       unless blob
         return error("You can only edit text files")
--
libgit2 0.21.2