Do you mean the first pension? It's not really frozen. If it's a defined benefit scheme based on the final/average salary then your final salary when you left will probably be revalued each year to reflect inflation and when you retire you'll get the benefits relating to 4 years' service. If it's a money purchase scheme then the value of your pot will be revalued periodically.
The second pension would probably still be carrying on into your current job as part of the TUPE transfer