Hi there! I dealt with BBA a while ago, and came at it from a bunch of different angles - I did full doses (but not doubles) of excel (directly on the algae), manually removed what I could, did vinegar dips, experimented with some week-long blackouts, decreased hours of lighting, and added in a couple Siamese Algae Eaters to eat the remainder (they did a great job)! In the end, I pretty much eliminated the BBA from that tank (actually, besides a teeny bit of green spot on the glass, my tank is algae free!!!)
In the end, I think the problem was my light. Using a timer, I’ve cut my lighting hours down to about 6 hrs per day, and the tank gets maybe an hour of nice full sunlight in the morning too. I suggest trying whichever of the above options you can, especially the lighting.