'Free Trial' Credit Voucher not deducted from bill (and was invoiced instead)

I received a £25 free trial voucher for the OVH Public Cloud.

To test the viability of an idea, I decided to spin up a couple of instances, leading to £19.87 (inc. VAT) of usage.

However, this usage has not been deducted from the cloud credit voucher and instead I have been issued an invoice/'order' for £19.87 (1st August) and one for £39.74 (2nd August).

(Note that £39.74 is twice £19.87.)

I really do not understand what is going on here.

First of all, the usage should have been fully covered by the voucher.

Second of all, this second invoice of £39.74 has completely appeared from thin air; I really don't understand that one at all.

Has anyone else ran into this problem?

I opened a support ticket about 24h ago but the expiry date on one of the invoices is 4th August (despite being issued on the 1st August...) and I don't have faith that I will get a response in that time.

Thanks.