Hi @billinVaurohe52
According to the bimonthly billing, the thing is, even if we switch it to the monthly billing now, the change will take effect on the next billing cycle. As you received your December and January invoice together, you will get February and March on the same invoice too and the monthly billing will start only for April.
If you don't want to wait beginning April to pay your February invoice, you can check your current usage on the 28th February and make your payment in advance.
Otherwise, it is possible to settle it once it is issued by credit card directly from your My Swisscom account or by bank transfer.
Here are the bank details for payment from abroad: https://bit.ly/3bDKlRE
Hope it helps!