Sick of Old Mutual automated calls

I'm having a terrible experience with Old Mutual. On weekdays without fail they call me and it's an automated call saying: "Hello. How are you?". Calls come in via different cellphone numbers and landline numbers from across the country. It interrupts me during working hours as I use my phone a lot for work and when it rings it's mostly these calls. I've had enough and I have blocked each number but they still come in.