Wrong product received

LC_88

2 weeks ago I received the wrong product which is worth considerably more than what I ordered. I contacted the seller straight away using their customer service link on website as they stated that due to the current situation there phone lines were off. So I waited a week but no reply. I emailed them again, another week has past with no reply.
What do I do? Obviously I want the product I ordered and paid for. And I also do not want to be charged for the product I received. 
What are my rights to keeping the much more expensive but still very useful product? 
Any advice on my legal standing would be muchly appreciated. 

JJ_Egan

<What are my rights to keeping the much more expensive but still very useful product? >

None and they have  6 years to pursue you .

Due to some virus restriction skeleton staff etc  things are taking longer than usual .