harassed until i had heart attack despite warning building society to stop

[Peaceful]

Just wondering do I have a case and how to proceed,, I missed one payment with a building society,,, they immediately started to harass me, phone calls, letter, during 3 phone calls I warned them that they were ging to induce a hear attack due to there continued harasment despite the fact that I agreed to pay the oversight,, subsequently I did have a heart attack,, and by pass,,,