Exorbitantly high consumption cots and sim blocked after monthly payment

Hello, 

My issue concerns an exorbitant amount (260,70€) accrued due to high consumption costs even after the money for the monthly bundle were withdrawn from my bank account. 

While I was browsing the internet on my way to work yesterday (27th of March) I get an SMS from Simyo saying that my sim is blocked due to high consumption and that I need to pay 100€ to unblock it. This initial shock was followed by perplexment since Simyo had charged me for my monthly bundle 3 days before, on the 24th of March. I was thinking to myself that there’s absolutely no way I spent 10gb of internet, and then some, in 3 days. I log on into my account to be faced with an even bigger shock, since the actual amount that the high consumption resulted in, was 260,70€!

After examining the charges, it appears that all of them concerned usage made from the 25th onwards, a day after I paid. I was reasonably under the impression that after you pay for something you have access to it. That was not the case apparently, since the website said that the bundle would be activated 5 days later. What’s the point of pre-paying for something but not having access to it immediately? Moreover, there was not sufficient information making it clear that there would be a gap between payment and activation of the bundle; something that lead to this whole debacle. From my experience with other phone service providers in other countries, this is a not-so-common practice

Besides the fact that I can in no way pay that amount of money in one go, this whole incident created huge distress for me while commuting to and during work. 

I would greatly appreciate some assistance on the matter.