Cash App complaint: A seller took my $100 and never send goods.

My complaint:

A seller on offerup with name kicksupplies asked me to make a payment for a shoe I had interest in on cash app. $100. Upon accepting the payment, he has refused to reply my messages . I asked for a refund and he refused. His cash app name is $kicksupplies ( SOZY)

Suggested solution:

I want cash app the help me get my $100 back thank you.