Just a quick question.

You have most likely clogged main sewer somewhere between the basement and the curb. You need to snake your sewer main line to restore drainage.

Milo nailed it! First rent a sewer machine, (see image) and then
Locate the house cleanout and open it up. Send the snake out to the city raiser at the curb, If you bring back roots let me know and we'll take it farther. Good luck, Tom