Need some advice because of bad roofing company

i contacted a company in birmingham to change my flat roof on march 2024 they did a really bad job cause it started leaking right away contacted them came to fix it but started leaking again after some time and they came to fix it like 4 times already now but it keeps leaking from new places and it started leaking today as well. Then i paid around £7000 for the roof. What can be done? Do i have to go small claims?