Is it a red flag

Contractor asked for 60% down payment on a 2100$ floor job only things they had to buy was some plywood maybe 4 slabs and the bonding cement and then during the job he stated he can’t really finish unless something else is done which I understand but why not say this in the beginning when u came and gave the estimate …(No sanding or removing of old plywood even tho it was needed he framed the tub but never removed it to clean up under or wasn’t placed on new plywood) ….. now granted i got busy and didn’t respond for two days to give him the ok on a new project but to then turn around and ask for 500$ more of the agreed amount for the FINISHED WORK ON AN UNFINISHED project which only required grouting left and to say just send the 300 when ur ready for me to finish … And then turns around and says he doesn’t do small projects but since I was referred by my cousin he did it anyway and claims he didn’t even over charger me… I thought he had more than enough to finish but am I wrong ….. ( job was tile on a 4x8 floor and just plywood on maybe a 10x10 floor just to see how good the work is I’m not giving u a big project just because)