Many thanks for your patience, I am pleased to be able to continue assisting with your query now. First of all, I am sorry to hear about this situation and any associated issues.
It is possible for one company to take over another one and for you to automatically transfer over to them. This is known as a TUPE transfer. TUPE is the acronym for The Transfer of Undertakings (Protection of Employment) Regulations 2006. If they apply to a transfer, those employees assigned to the transferring business will automatically move to the new employer on their existing contractual terms and conditions. Simply put, the new employer would 'step into the shoes' of the old employer and the employees should start working for the new business as if nothing had changed, apart from the name of their employer.
However, you should have been informed and consulted over the proposed transfer and if they failed to do that and you only found out about it once you had transferred, you can potentially challenge them and accuse them of failure to carry out their legal obligations.
If you had to make a claim for it you will need to contact ACAS, either online by filling in the following form (https://tell.acas.org.uk/find-a-solution-to-your-employment-dispute), or by phone on 0300(###) ###-#### They will explain the process and what happens next and get the ball rolling on your behalf.