High end kitchen company - finding it difficult to get them to complete the work

[Mothergoose]

I have a very small kitchen and the cabinetry and went for bespoke cabinetry from a quite well known company. Unfortunately, their project management and communication was very poor - the cabinetry without trades or worktop was 24k. Our kitchen was left half way through for a week as there were cornices, handles, doors that were still waiting to be delivered though the kitchen had been paid for upfront three months ago. We're now waiting for them to do the adjustments needed as requested by the Stone templater. We have been without a kitchen for five weeks. They would only take upfront payment so all the cabinetry has been paid for. Any ideas on how to progress this. The kitchen company recommended the stone company.