i’ve gotten cells from liionwholesale.com and was very pleased with the cells/service.
have also used imrbatteries.com with no complaints… aside from their name being a bit misleading (chemistry of cells). then again A LOT of folks abusing ‘IMR’.
Mooch has a list of ‘Some good vendors’ for the US, and EU.
https://www.e-cigarette-forum.com/blogs/mooch.256958/