1gb card + 3gb barely working

I've bought a card with 1gb and then bought 3gb. I've used up my first gb of the internet and after that it's not properly working. The speed is super slow. Looks like I don't use my other 3gb.ive checked my account and money are there. Now I'm in the Netherlands so can't go to o2 and ask. Also it's a problem to call support drone here. I don't see a live chat either.

what should I do? Maybe this is pretty silly topic but this problem drives me insane