Hi there @Dimosthenis Schizas - sorry that you're having to deal with that. You can change your account to Standard without any charges by going to Account -> Your Plan -> Upgrading your plan.
You'll have to enter a credit card, but if you stay under the 20,000 run limit (as on the current tier you're on), you won't be charged.
If that's not an option for you just DM me and we'll help you out!