Might depend on the location as there are many...now having said that, I know that the one in Negril is not open on Sundays and have a feeling like a lot of businesses in JA they are not. So you might have to make a few phone calls to the closest location to where you are going to be to find out...here is what I found on locations.
Kingston - SERCURE SERVICES - 57 Duke Street Kingston, +876-929-1331
Kingston - SUPER PLUS FOOD STORE - 15 17 Half Way Tree Road Kingston, +876-926-2454
Kingston - TRU NORTH VENTURES LTD - 7 Pechon Street Kingston, +876-929-1331
Kingston - XXTRA SUPERMARKET - 105 Red Hills Road Kingston 19 Kingston, +876-926-2454
May Pen - ACCESS FINANCIAL SERVICES LTD - Shop 12 Bargain Village May Pen, +876-926-2454
May Pen - GSD PHARMACY - 55 A Manchester Ave May Pen May Pen, +876-926-2454
May Pen - MAY PEN FSC - 11 Brook Avenue May Pen, +876-926-2454
May Pen - PARKVIEW SUPERMARKET - 26 Main Street May Pen May Pen, +876-926-2454
Spanish Town - FUTURE OPTIONS - 363 Willowdale Parkway Old Harbor Rd Spanish Town, +876-926-2454
Spansh Town - HOLLIFON FINANCIAL SERVICES - Loj Shopping Center Spanish Town, +876-926-2454
Spanish Town - JAMPET - 48 50 Brunswick Avenue Spanish Town, +876-926-2454
Spanish Town - VALLEJAH - Tj'S Variety Shop #11 Angels Plaza Spanish Town, +876-929-1331
Spanish Town - WU ST JAGO SHOPPING CEN - St Jago Shopping Centre Shop 28 Spanish Town, +876-929-1331