Harassed by phone calls and messages for months

Constant phone calls and SMS messages. I've tried to send the stop message but nothing stops. I phoned to be removed from their list and could not speak to an agent without inputting my ID number. Now I receive multiple messages a day to 'complete my application'. Also receiving daily phonecalls that say 'please hold for an important call' over and over for a few minutes and then puts down on me so I can't speak to anyone. At this stage I would call this harrassment, honestly. I will have to contact the Ombudsman it seems.