In case of issues it will take a long time
I bought a 1 year PS Plus activation code and received it promptly after buying it. I had still a few days left of my previous subscription so I wasn't able to activate it immediately as it's not possible with active subscription. After my previous subscription ended I tried to activate the code I bought but I received an error that the code had already been used. I contacted the customer support first via chat, where I was promised a reply via email during 48 hours but I didn't get one even after 72 hours. I returned to the chat and didn't get any help at all anymore. After that I contacted the customer support via email. That way it took more than a week (during which I asked about my case many times) to get a new activation code. So because of this ineffective customer support I ended up being 2 weeks without PS Plus subscription. I did get what I bought eventually, but I wasn't happy that I had to wait so long and I feel it took too long and the customer support didn't seem to care at all, especially in the chat support.