MK1 and MK2 are too vague and cabinets work at the premise level
The only way to know is to share more detail than you should in public...
i.e. who is phone line provider
postcode and address
If you want me to look at this then best to email me email@example.com
The words where you said 'it is all used up' suggests maybe your cabinet is enabled, but there is a capacity issue i.e. service is very popular and more ports or other elements are needed so you can be connected.
The capacity issue can be checked by just telling us which exchange the cabinets are connected to.