Unpaid claim since 2015

My son passed away 2015 I haven’t received payment and it has been almost 5 years, today I received a a call insulting me,they say after investigating the found out that he was not my son, I don’t know what bull is that and which investigators did they hire who come up with such ****, it was better when they were telling me that they are still investigating but to phone and tell nonsense, I don’t know which drugs they are taking.