Plan changing - will all options always be available?

Hi.

First of all, the fact that I cannot call customer services and even email them with a question is absolutely ridiculous.

My questions do need to be answered by someone who specifically works for ID mobile and can actually advise me 100% correctly, because having the correct information will change what I do.

I want to change my plan, but may need to change it back again between an increased option and a decreased option.

My contract ends in February 2021. I have 1GB. Im paying £23.61/month. To get 50GB its £38.99/month and unlimited is £45.99/month.

So, if I use the app and select 50GB, can I then go back to 1GB for £23.61/month after 30days? Can I also increase it to unlimited for £45.99/month or will these not be options if I change my plan to the 50GB one?

The reason for me asking this is circumstantial so I may need more or less data.

There is no information about if I select an option, what my future options will be. Will these be my only options during the contract period?

I may need to cancel my contract with ID mobile and just get unlimited from three, if I don’t get a concrete definitive answer.

Thank you.