Premium holiday

I have a policy from old mutual...i was unemployed from 2020 June..the i app**** for premium holiday of six months from November to April 2021...after premium holiday expired i was still unemployed but managed to pay for May,June then July i was employed...so things went back to normal...oned day i received a call from old mutual saying my policy is behind for 3 months...asked how..they explained to me that i have to pay 3 months from premium holiday becouse it was for 4 months...i was shocked becouse i signed fir 6 months, now why should i pay.