Because you did not explain the nature of your store. Based on your description, I guess it may be an individual business owner.
The first thing to do is to clarify several legal relationships.
1. You (A) and the transferor (B)
2. B and the landlord (C)
One more thing you need to know whether it is an individual business Whether it is a household or a legal person, its transfer requires a procedure for changing the business license. The industrial and commercial departments have a complete procedure for this change procedure. If you have not carried out this procedure, then in fact this store is still owned by the original owner B. As you stated, you may not have registered the change.
Secondly, you must retain evidence of all reasonable expenses incurred by you in operating the store during the period of operation to recover compensation from B. You also have to return the profits generated during the business period to B. B also needs to return the so-called transfer fee you paid (in fact, your transfer is only a conscious transfer, not a legal transfer). The reason is that B has now regretted his unwillingness to sell the store. In fact, the store has not been transferred legally, so your transfer contract has been established but has not taken effect. (I don’t know what the content of your transfer contract is. I just judge it based on your description. You can add it yourself later.)
Finally, let’s talk about the issue with the landlord. In fact, the landlord rented the house to B. You only actually ran a shop for B for a period of time and did not actually rent the house. Therefore, the lease contract for this house is still between B and C.
Your problem is actually a bit complicated, but it should be resolved through negotiation between the two parties.