How to fix cydia, mail and safari not openingon a jailbroken iphone 4s running ios 7.1.2

[Azi ipa fan]

i have a phone 4s on ios 7.1.2 that i bought on ebay that i jailbroken with pangu however at some point it just wont open cydia, safari and mail. So if any of you know how to solve the problem please reply it to this/my post please. Thank you in advance