My group chat only messages me when they need someone to pay first and wait to get paid back

Every dinner, concert, and trip starts with "can you book it, we'll send it later". Two of them still owe me from last month. I said I was tight on cash once and the chat went quite for days. I tried asking for the money directly and I tried suggesting we split apps instead. I miss hanging out, but I don't want to keep being the bank.