Don't use eval but get a reference to the code you want to call, and call that like any other subroutine:

use Carp qw(croak);
sub call_service {
   my $svc  = shift;
   my $cmd  = shift;
   my @args = @_;

   my $name = "$svc\::$cmd";
   my $handler = *{$name}{CODE};
   croak "Couldn't find a handler for $name"
     unless $handler;

   # maybe log the invocation to your logfile?

   return $handler->(@args);
}
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This code is untested, sorry - maybe you need to take a reference like

my $handler = \*{$name}{CODE};
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instead - sorry for not testing my stuff out.