Reply delays Class 3 NIC top up simulations and financial consequences

Hello, I live in France and I currently get the New State Pension .In November 2023 I contacted by email the International pension centre in order to get information on pension top ups since I only have 24 qualifying years. Without any reply to date,and despite several phone calls , each time with a different answer, how long does it take to deal with such enquiries ? This is important as top up increase in cost each financial year.

Hi WOODY43 IGOE,
The Pension Service are responsible for the payment of the UK State Pension and will be able to give you information about paying additional voluntary National Insurance contributions as you are now over UK State Pension Age.  
May I ask that you contact the International Pension Centre to ask them for an update on your query.  
Their telephone number is +44 191 2187777.  
Their postal address is:  
The Pension Service,
Post Handling Site A,
Wolverhampton
WV98 1AF,
United Kingdom
Thank you.