How do I get the value from a class property in Objective-C?

I want to get variable value from an objective-c class, using reflection.

company.h looks like

@interface Company : NSObject {
}
@property (nonatomic, retain) NSString* phone;
- (NSString*) getPropertyValueByName: (NSString*) paramName;

company.m looks like

@implementation Company
@synthesize phone;
- (NSString*) getPropertyValueByName: (NSString*) paramName
{    
    id me = self;
    value = [me objectForKey: paramName];
    return value;
}
@end

I am using this like:

Company* comp = [Company new];
comp.phone = @"+30123456";

NSString* phone = comp.getPropertyValueByName(@"phone");

What I am getting is an exception:

-[Company objectForKey:]: unrecognized selector sent to instance