Around January, I bought an Ultegra DI2 drivetrain group set
The seller said there was nothing wrong with it
After purchasing, I went to the shop and had it installed
After installation, the weather got cold so I put it away, and now that the weather has warmed up a bit
I rode it and oil started leaking out
Something seemed wrong so I went to the shop, and they said there were oil residue remaining from the bleeding process
They told me it could be leaking out
Thinking that was the case, when I rode it again, I realized the brake hydraulic pressure wasn't holding
Thinking something was wrong
I went back to the shop, explained the situation, and asked them to inspect it again
Now they're saying there's oil leakage from the lever cylinder
When they disassembled it, they said it's been built up over a long time
What should I do if something like this happens?
