Was told by my waitress that she only gets cash ti...

Was told by my waitress that she only gets cash tips due to only being paid 3 dollars and hour. Then walk to the counter to pay my bill and the cashier turns her iPad around for me to indicate how much of a tip I wanted to leave on my debit card? A bit skeptical? I advised the CASH tip on the table! The waitress even indicated she really was not suppose to tell us that she can only have cash tips and that we couldn't put tip on debit or credit card? I would rather spend my money elsewhere and the chicken and sausage jambalaya was dry and not edible.