InAppPurchase2 in ionic3

plugin giving error when i install

Failed to install ‘cc.fovea.cordova.purchase’: Error: Forward-slash in opening tag not followed by >
Line: 0
Column: 107
Char: d

Failed to install ‘cc.fovea.cordova.purchase’: CordovaError: Uh oh!
“F:\IndiansInCA\platforms\android\app\src\main\res\values\billing_key_param.xml” already exists!
at copyNewFile (F:\IndiansInCA\platforms\android\cordova\lib\pluginHandlers.js:259:45)
at install (F:\IndiansInCA\platforms\android\cordova\lib\pluginHandlers.js:43:17)
at ActionStack.process (F:\IndiansInCA\platforms\android\cordova\node_modules\cordova-common\src\ActionStack.js:56:25)
at PluginManager.doOperation (F:\IndiansInCA\platforms\android\cordova\node_modules\cordova-common\src\PluginManager.js:114:20)
at PluginManager.addPlugin (F:\IndiansInCA\platforms\android\cordova\node_modules\cordova-common\src\PluginManager.js:144:17)
at F:\IndiansInCA\platforms\android\cordova\Api.js:247:74
at _fulfilled (F:\IndiansInCA\platforms\android\cordova\node_modules\q\q.js:834:54)
at F:\IndiansInCA\platforms\android\cordova\node_modules\q\q.js:863:30
at Promise.promise.promiseDispatch (F:\IndiansInCA\platforms\android\cordova\node_modules\q\q.js:796:13)
at F:\IndiansInCA\platforms\android\cordova\node_modules\q\q.js:556:49
[ERROR] An error occurred while running cordova plugin add cc.fovea.cordova.purchase --variable
BILLING_KEY=<M… (exit code 1).