Handle generic types in GetMethod

What would be the correct arguments for GetMethod in the AddService(services, type, instance) exactly defining the generic version (just in case there will come more overloads).

I know I could just keep the method names different but I don't want to.

Currently I get either null or an exception due to multiple found method versions...

The code:

namespace Sample
{

    public interface IService { }

    public static class SampleExtensions
    {

        public static IServiceCollection AddService<T>(this IServiceCollection services, T instance) where T : IService
        {
            //services.AddSingleton<T>(instance);
            services.AddSingleton(instance.GetType(), instance); // register with the concrete implementation type
            //some stuff that only works with generic T
            return services;
        }

        public static IServiceCollection AddService(this IServiceCollection services, Type type, object instance)
        {

            Type classType = typeof(SampleExtensions);
            MethodInfo methodInfo = classType.GetMethod                         // correct arguments??
            (
                nameof(AddService),                                             // only name would bring 2 results
                new Type[] { typeof(IServiceCollection), typeof(object) }       // ??? instance is generic
            );
            MethodInfo genericMethod = methodInfo.MakeGenericMethod(type);
            genericMethod.Invoke(null, new[] { services, instance });           // call the generic method version
            return services;
        }

    }
}