Resoponse are not consistent GetQuote

I am calling GetQuote method but results are not consistent.

output:

Exception thrown: 'System.Collections.Generic.KeyNotFoundException' in mscorlib.dll
DEBUG: 429 {"status": "error", "message": "Too many requests", "error_type": "NetworkException"}

DEBUG: GET https://api.kite.trade/instruments/NSE/VEDL?access_token=***&api_key=***

DEBUG: 200 {"status": "success", "data": {"last_price": 348.45, "volume": 3043180, "sell_quantity": 928637, "open_interest": 0.0, "last_quantity": 19, "change": 8.45, "ohlc": {"high": 352.05, "close": 340.0, "open": 338.9, "low": 338.8}, "last_time": "2018-01-25 09:50:29", "change_percent": 2.48, "depth": {"sell": [{"price": 348.45, "orders": 1, "quantity": 6}, {"price": 348.5, "orders": 1, "quantity": 139}, {"price": 348.55, "orders": 1, "quantity": 200}, {"price": 348.6, "orders": 2, "quantity": 260}, {"price": 348.65, "orders": 5, "quantity": 998}], "buy": [{"price": 348.4, "orders": 1, "quantity": 500}, {"price": 348.3, "orders": 6, "quantity": 3885}, {"price": 348.25, "orders": 10, "quantity": 5728}, {"price": 348.2, "orders": 12, "quantity": 5510}, {"price": 348.15, "orders": 15, "quantity": 8670}]}, "buy_quantity": 697894}}

DEBUG: GET https://api.kite.trade/instruments/NSE/VEDL?access_token=***&api_key=***

Exception thrown: 'System.Collections.Generic.KeyNotFoundException' in mscorlib.dll
DEBUG: 429 {"status": "error", "message": "Too many requests", "error_type": "NetworkException"}

DEBUG: GET https://api.kite.trade/instruments/NSE/VEDL?access_token=***&api_key=***

DEBUG: 429 {"status": "error", "message": "Too many requests", "error_type": "NetworkException"}

Exception thrown: 'System.Collections.Generic.KeyNotFoundException' in mscorlib.dll
DEBUG: GET https://api.kite.trade/instruments/NSE/VEDL?access_token=***&api_key=***

DEBUG: 200 {"status": "success", "data": {"last_price": 348.45, "volume": 3043352, "sell_quantity": 930038, "open_interest": 0.0, "last_quantity": 43, "change": 8.45, "ohlc": {"high": 352.05, "close": 340.0, "open": 338.9, "low": 338.8}, "last_time": "2018-01-25 09:50:29", "change_percent": 2.48, "depth": {"sell": [{"price": 348.55, "orders": 1, "quantity": 200}, {"price": 348.6, "orders": 3, "quantity": 409}, {"price": 348.65, "orders": 6, "quantity": 1378}, {"price": 348.7, "orders": 14, "quantity": 5126}, {"price": 348.75, "orders": 9, "quantity": 8935}], "buy": [{"price": 348.45, "orders": 1, "quantity": 5}, {"price": 348.4, "orders": 1, "quantity": 351}, {"price": 348.3, "orders": 6, "quantity": 3885}, {"price": 348.25, "orders": 10, "quantity": 5728}, {"price": 348.2, "orders": 13, "quantity": 5659}]}, "buy_quantity":

Exception thrown: 'System.Collections.Generic.KeyNotFoundException' in mscorlib.dll
DEBUG: 429 {"status": "error", "message": "Too many requests", "error_type": "NetworkException"}