New York, Nov 29 (IANS) The rising levels of Apple calendar spamming is frustrating the Cupertino-based tech giant's iPhone or iPad customers by "reminding" them of buying stuff they never asked for, the media reported on Tuesday. Apple's calendar app allows invites to be sent by unauthenticated users and pushed directly to a handset, a report in Forbes said. "You get a bubble alert on the calendar app, text in your inbox you have to read and depending how you have set up your device you might get a 'useful' notification that you have no choice but to read and clear," the report pointed out. The problem that Apple may face with this issue is that the success of this route to potential customers will become a popular route for spammers. According to the report, being able to mark invites as spam, to be able to blacklist addresses and to have some processing done on the server side to stop a flood of invites from a single source may help the customers deal with the issue. "If this can be implemented quickly, then calendar spam would be nothing more than a short-term annoyance," the report said. Until Apple finds a permanent solution to this problem, the tech giant's loyalists could push all spam requests into a separate calendar and then deleting that calendar eventually swiping out all the entries at once. Users may also change iCloud calendar settings from desktop to invite notifications from 'in-app' to 'email' and use email client to filter the spam.