I am expecting two separate jsons in case of success and failure. 

In case of success I get a nested json whereas in failure I get a simple json mentioning status : failed so my class I used to handle success is failing for failure scenario. Can someone please guide here?
Only way I can think in checking the substring of json and validate before parsing but that doesn't seem a good solution.

Updated Jsons: 
**Success:**
   

    {
    	"Subscriptions": [
    		{
    			"Subscription": {
    				"SAPOrder": "SAP123",
    				"RequestType": "New",
    				"OrderStatus": "0",
    				"Services": [
    					{
    						"Service": [{
    							{
    								"attribute": {
    									"name": "Resilience",
    									"value": "Terminated"
    								}
    							},
    							{
    								"attribute": {
    									"name": "Number",
    									"value": "1234"
    								}
    							},
    							{
    								"attribute": {
    									"name": "serviceStartDate",
    									"value": "2018-08-220T02:13:20"
    								}
    							}
    						},
    							{{
    								"attribute": {
    									"name": "Resilience",
    									"value": "Terminated"
    								}
    							},
    							{
    								"attribute": {
    									"name": "Number",
    									"value": "1234"
    								}
    							},
    							{
    								"attribute": {
    									"name": "serviceStartDate",
    									"value": "2018-08-220T02:13:20"
    								}
    							}
    						}
    						]
    					}
    				]
    			}
    		}
    	]
    }


**Failure:**

      {
        	"Subscriptions": [
        		{
        			"Subscription": {
        				"SAPOrder": "SAP123",
        				"RequestType": "New",
         				"OrderStatus": "Failed"
                    }
                }

**Added Class details:**


    public class JSON2Apex {
    
    	public class Services {
    		public List<Service> Service;
    	}
    
    	public List<Subscriptions> Subscriptions;
    
    	public class Attribute {
    		public String name;
    		public String value;
    	}
    
    	public class Subscriptions {
    		public Subscription Subscription;
    	}
    
    	public class Service {
    		public List<Attribute> attribute;
    	}
    
    	public class Subscription {
    		public String SAPOrder;
    		public String RequestType;
    		public String OrderStatus;
    		public List<Services> Services;
    	}
    
    	
    	public static JSON2Apex parse(String json) {
    		return (JSON2Apex) System.JSON.deserialize(json, JSON2Apex.class);
    	}
    }